                            PUBLISHED

UNITED STATES COURT OF APPEALS
                FOR THE FOURTH CIRCUIT


UNITED STATES OF AMERICA,              
                 Plaintiff-Appellee,
                 v.                             No. 02-4194
FRANCISCO CURBELO, a/k/a Murando,
              Defendant-Appellant.
                                       
UNITED STATES OF AMERICA,              
                 Plaintiff-Appellee,
                 v.                             No. 02-4247
FRANCISCO CURBELO, a/k/a Murando,
              Defendant-Appellant.
                                       
            Appeals from the United States District Court
      for the Western District of North Carolina, at Charlotte.
              Graham C. Mullen, Chief District Judge.
                         (CR-99-109-MU)

                         Argued: April 3, 2003

                      Decided: September 11, 2003

          Before WILKINS, Chief Judge, and MOTZ and
                    KING, Circuit Judges.



Vacated and remanded by published opinion. Judge King wrote the
majority opinion, in which Judge Motz joined. Chief Judge Wilkins
wrote a dissenting opinion.
2                      UNITED STATES v. CURBELO
                              COUNSEL

ARGUED: Lisa S. Costner, LISA S. COSTNER, P.A., Winston-
Salem, North Carolina, for Appellant. Gretchen C.F. Shappert,
OFFICE OF THE UNITED STATES ATTORNEY, Charlotte, North
Carolina, for Appellee.


                              OPINION

KING, Circuit Judge:

   On July 13, 2001, an eleven-person jury convicted Francisco Cur-
belo of multiple counts related to a drug distribution ring that oper-
ated out of Charlotte, North Carolina. Curbelo has asserted several
possible grounds for reversal, including the district court’s decision to
proceed, over his objection, with eleven jurors. The Government con-
cedes that the court erred in proceeding with an eleven-person jury,
but it asserts that the error was harmless and that Curbelo’s convic-
tions should therefore be affirmed. Every court to have addressed the
question has held to the contrary, and we decline to deviate from this
consensus. Thus, we vacate Curbelo’s convictions and remand for a
new trial, without reaching his other assertions of error.

                                   I.

   On July 13, 1999, a grand jury in the Western District of North
Carolina returned its initial indictment against Curbelo, charging him
with multiple drug and firearms violations. A superseding indictment
was returned on February 6, 2001, and it serves as the basis for his
convictions. The superseding indictment alleges that Curbelo and oth-
ers engaged in a drug conspiracy between January 1996 and June
1999. Count One of the superseding indictment charged Curbelo with
a controlled substances conspiracy, in violation of 21 U.S.C. § 846;
Counts Two, Four, Five, Seven, Nine, and Eleven charged him with
possession with intent to distribute cocaine base, in contravention of
21 U.S.C. § 841; and Counts Three, Six, Eight, Ten and Twelve
charged him with possession of firearms in relation to drug trafficking
offenses, in violation of 18 U.S.C. § 924(c).
                       UNITED STATES v. CURBELO                          3
  On July 9, 2001, a jury of twelve was impaneled for Curbelo’s trial.1
The jurors were sworn shortly after 4 o’clock that afternoon, and
counsel for both sides then presented their opening statements. The
Government then called its first and principal witness, an alleged co-
conspirator, Thurnell Williams. At approximately 5:00 p.m., the trial
was adjourned for the day, resuming the next morning around 9:30.
At about 5 o’clock on the afternoon of July 10 — after Williams had
completed his direct testimony, but not his cross-examination — court
was adjourned early because of an air conditioning problem in the
courthouse.

   On the morning of July 11, 2001, before the start of the third day
of what would be a five-day trial, the court informed the parties that
"[o]ne of our jurors has called in sick and will have to be excused."
In response, the prosecution suggested that the parties stipulate to pro-
ceeding with only eleven jurors. Although Curbelo declined to so
stipulate, the court nevertheless announced:

      It appears that the Court finds it necessary to excuse one
      juror for just case [sic] after the trial commences. [The
      juror’s] father having called in and reported she’s suffering
      from irritable bowel syndrome and is totally unable to func-
      tion. She has been instructed to report to court with a doc-
      tor’s certificate after she recovers from whatever this is. But
      I believe the Court has discretion to proceed with 11 absent
      the stipulation, and we will proceed.

Thus, the court ruled, over Curbelo’s objection, that his trial should
proceed with eleven jurors, even though the trial was still in its infant
stages — with the first witness still on the stand.

   That witness, Thurnell Williams, provided a good deal of the evi-
dence against Curbelo. Williams, who supported himself by selling
crack, testified that on several occasions, from late 1996 through June
1999, he purchased illegal narcotics from Curbelo. Around the end of
1998 or the beginning of 1999, Williams stopped dealing with Cur-
belo because he owed and could not repay Curbelo $12,000, appar-
  1
   The court did not impanel any alternate jurors for Curbelo’s trial.
4                     UNITED STATES v. CURBELO
ently for illegal drugs. Later in 1999, when law enforcement agents
"repeatedly" told Williams that he was "a target of a federal investiga-
tion," he agreed to "assist the government and become an informant."
Working with the agents, Williams started dealing with Curbelo
again. Because Curbelo did not speak much English, various people,
including a man named Jose, helped Williams negotiate with Curbelo.
According to Williams, the purchases often took place in Curbelo’s
phone store, with Jose’s translation and assistance. (Jose worked for
Curbelo at the store.) Further, Williams testified that Curbelo kept a
microwave and firearms in the back of the store, where he sometimes
microwaved the cocaine into crack. During several of his interactions
with Curbelo, Williams wore a wire and a video camera; the Govern-
ment played these tapes, and provided photographs and transcripts of
these meetings to the jurors.

   Williams acknowledged that during the 1990s he was convicted
and imprisoned in Florida for assault, trafficking in cocaine and pos-
session of a firearm during the commission of a felony, and that in
July 1999 (after he had begun work for law enforcement) he was con-
victed of theft and possession of a firearm. On cross-examination,
defense counsel asked Williams about (1) his failure to mention Cur-
belo’s possession of guns in his initial reports to police; (2) a confi-
dential informant’s statement that contradicted a portion of
Williams’s testimony; and (3) an allegation that Williams had pur-
chased a cellular phone from Curbelo’s store and that Williams’s
unpaid debt was actually owed in connection with that purchase,
rather than for illegal drugs.

   Regarding his interactions with Curbelo, Williams admitted that on
multiple occasions Curbelo explicitly refused to provide him with any
cocaine, stating that he only had access to marijuana. Williams also
acknowledged that Jose actually "handed" him "the drugs" every time
he purchased them while working with law enforcement officers. On
the first such occasion, June 15, 1999, Jose told him that Curbelo
would not be there and to "talk to him [Jose]." The next day when
Williams called, Curbelo again was away from the store, and Wil-
liams asked Jose for cocaine; in paying for the cocaine, Williams
attempted to hand the money to Curbelo (as instructed by the agents),
but Jose took the money and counted it himself. Williams also agreed
that the "other times that [he had] s[aid] [he] saw Mr. Curbelo cook-
                       UNITED STATES v. CURBELO                           5
ing cocaine or the other times that [he] [said] [he] dealt with Mr. Cur-
belo, none of that is actually documented on tape or a transcript or
audiotape or anything like that." And, "[t]here is no physical evidence
of any of those transactions at all."

   Six other alleged drug dealers or co-conspirators testified more
briefly; most were imprisoned and testified under plea agreements.
On direct examination, they corroborated various aspects of Wil-
liams’s testimony; on cross-examination they contradicted themselves
and each other on some issues. For example, one of the other wit-
nesses testified in detail that, with Williams’s knowledge and encour-
agement, he had robbed Curbelo’s store and kidnaped Curbelo’s
girlfriend, Wendy. However, when Williams testified, he had denied
knowing anything about the robbery or kidnaping.

   In addition, two Government agents testified;2 they related their
conversations with Williams and observations of Curbelo. They
acknowledged that no law enforcement officers accompanied Wil-
liams into Curbelo’s store, that other than what was shown on video,
they could not see what was happening in the store, that the quality
of some of the video was "poor," and that the video did not "show
who was actually transferring the drugs." Furthermore, they admitted
that on the tapes, Williams’s references to drugs ("ounces") were only
made when he was talking to Jose, and that when he talked about pay-
ing down his debt to Curbelo, he "never ma[de] a reference to drugs."
Finally, they conceded that Williams had not been charged with
Wendy’s kidnaping, or the robbery of Curbelo’s store, or his drug
dealing in North Carolina prior to his cooperation with law enforce-
ment authorities, or his possession of a firearm by a convicted felon.

   Curbelo took the stand in his own defense and testified through an
interpreter. According to Curbelo, in January 1999, Williams started
coming to Curbelo’s recently opened store to look at some of the
  2
    The Government also presented the testimony of an interpreter, who
reviewed the transcripts of the tapes prepared for the jury; the interpreter
testified that there were some omissions in the transcripts, but that they
were "well over 95 percent correct." He acknowledged that the tapes
were noisy and that it was "difficult to maintain whom is talking to
whom."
6                     UNITED STATES v. CURBELO
phones. Williams was "very insistent about drugs," "always telling
[Curbelo] that he knew people in New York [who] had drug sources."
Curbelo, however, denied ever selling drugs to Williams. Curbelo’s
lawyer asked Curbelo about one of the tapes on which it appeared that
Curbelo was saying "kilo." Curbelo explained that the police did not
respond after the robbery of his store, that he suspected Williams, and
that he used the word "kilo" in an effort to set a trap for Williams to
come back to the store and try to rob it again. He said that he later
found out that Jose did give Williams drugs, but that he and Jose had
only talked about "a pretend simulated drug business to try to trap"
Williams and obtain evidence on him. Curbelo also testified that it
was "impossible" that Williams saw him cooking crack cocaine in a
microwave oven in the back of the store, because "Wendy was scared
to death" of Williams and he and Wendy "would never have him go
past the counter."

   Curbelo acknowledged that he knew many of the witnesses who
testified but denied that he dealt drugs with any of them. He testified
that one of his alleged co-conspirators told him in the holding cell that
his testimony against Curbelo "was nothing personal against [Cur-
belo], but he just wanted to get free," and that "they were going to
give him his freedom for coming here and lying in his testimony."
Curbelo also maintained that the tapes played to the jury were not
accurate and had been edited and "tampered with."

   The eleven-person jury returned its verdict on July 13, 2001, con-
victing Curbelo of the conspiracy count and of the six counts of pos-
session with intent to distribute cocaine base. He was acquitted of all
five firearms charges. On March 20, 2002, the court conducted a sen-
tencing hearing. At the hearing, the district judge found that Curbelo
had lied under oath at trial, but the judge also stated that he was
"highly skeptical of some of the truthfulness of Mr. Williams, in par-
ticular in his inability to admit the truth that he had anything to do
with the robbery." The court sentenced Curbelo to seven concurrent
sentences of 360 months, plus seven concurrent terms of five-years
of supervised release. Curbelo has appealed, and we possess jurisdic-
tion pursuant to 28 U.S.C. § 1291.

                                   II.

   Curbelo contends that he is entitled to a new trial because the dis-
trict court, in the midst of his trial and without his consent, dismissed
                       UNITED STATES v. CURBELO                         7
one of his jurors and permitted eleven jurors to hear the evidence and
decide his fate. In response, the Government concedes that the court
did err in proceeding with an eleven-person jury, but it contends that
the error was harmless and that Curbelo’s convictions and sentence
should be affirmed.

   The Supreme Court has established various standards for determin-
ing when an error requires that a criminal defendant’s conviction be
vacated. For most constitutional errors, the Government must demon-
strate that the error was harmless beyond a reasonable doubt. Chap-
man v. California, 386 U.S. 18, 24 (1967). And for most
nonconstitutional errors, the Government must demonstrate that the
error did not have a "substantial and injurious effect or influence in
determining the jury’s verdict." Kotteakos v. United States, 328 U.S.
750, 776 (1946). Finally, some errors, involving "‘structural defects
in the constitution of the trial mechanism . . . defy analysis by
"harmless-error" standards,’" because they are "necessarily unquanti-
fiable and indeterminate." Sullivan v. Louisiana, 508 U.S. 275, 281-
82 (1993) (quoting Arizona v. Fulminante, 499 U.S. 279, 309 (1991)).
Such errors always require invalidation of a judgment. Id. at 279.
Determining the character of the error at issue in this case presents
some difficulties.

   Clearly this error violated Fed. R. Crim. P. 23(b), which entitles a
defendant tried in federal court to a twelve-person jury. At the time
of Curbelo’s trial, Rule 23(b) provided that:

      Juries shall be made of 12 but at any time before verdict the
      parties may stipulate in writing with the approval of the
      court that the jury shall consist of any number less than 12
      or that a valid verdict may be returned by a jury of less than
      12 should the court find it necessary to excuse one or more
      jurors for any just cause after trial commences. Even absent
      such stipulation, if the court finds it necessary to excuse a
      juror for just cause after the jury has retired to consider its
      verdict, in the discretion of the court a valid verdict may be
      returned by the remaining 11 jurors.

Fed. R. Crim. P. 23(b) (2002).3 Pursuant to this Rule, Curbelo was
  3
   Rule 23 was amended on December 1, 2002, "as part of the general
restyling of the Criminal Rules to make them more easily understood."
8                       UNITED STATES v. CURBELO
entitled to be tried by a twelve-person jury, and the district court pos-
sessed no discretion — prior to deliberations — to conduct the trial
with an eleven-member jury, absent Curbelo’s consent.4 Indeed, the
Government candidly concedes that the court violated Rule 23(b) in
proceeding, over Curbelo’s objection, with eleven jurors.

   In addition, the jury right embodied in Rule 23(b) unquestionably
has constitutional dimensions. First, two provisions of the Constitu-
tion relate specifically to the right to trial by jury. Article III, § 2, cl.
3, provides: "The Trial of all Crimes . . . shall be by Jury." U.S.
Const. Art. III, § 2, cl. 3. Similarly, the Sixth Amendment provides:
"In all criminal prosecutions, the accused shall enjoy the right to a
speedy and public trial, by an impartial jury of the State and district
wherein the crime shall have been committed." U.S. Const. Amend.
VI.

   Moreover, the right to trial by jury has a long and venerable his-
tory. See generally Duncan v. Louisiana, 391 U.S. 145 (1968).
Indeed, "by the time our Constitution was written, jury trial in crimi-
nal cases had been in existence in England for several centuries and
carried impressive credentials traced by many to [the] Magna Carta."
Id. at 151. Thus, the right to a jury trial was one of the most important
protections placed in the Constitution. See id. at 149 ("[T]rial by jury
in criminal cases is fundamental to the American scheme of justice.");
Patton v. United States, 281 U.S. 276, 312 (1930) ("[T]he right of the
accused to a trial by a constitutional jury [must] be jealously pre-
served."). Although the Supreme Court initially interpreted the Con-
stitution to preserve the twelve-person jury safeguard as it was known
at common law in all courts in the United States, see Thompson v.
Utah, 170 U.S. 343, 350-51 (1898); see also United States v. Va.

See Fed. R. Crim. P. 23, Advisory Committee Notes to 2002 Amend-
ments. The revisions were "intended to be stylistic only," id., and they
have no bearing on this appeal.
  4
    The language of Rule 23(b) is clear and unequivocal. Strikingly, how-
ever, the Government advised us at oral argument that "nobody picked
up a rule book," that "none of the lawyers read the Rule," and that "if the
parties had read Rule 23(b), as opposed to relying upon their memories,
we wouldn’t have this issue before the Court."
                       UNITED STATES v. CURBELO                          9
Erection Corp., 335 F.2d 868, 871 (4th Cir. 1964) ("Twelve is the
magic number."), more recently it has held that the Sixth Amendment,
as applied to the states through the Fourteenth, does not entitle a
defendant tried in state court to a twelve-person jury. See Williams v.
Florida, 399 U.S. 78, 89-90 (1970). In view of this holding and the
fact that our court and other courts have upheld the constitutionality
of Rule 23(b), see, e.g., United States v. Fisher, 912 F.2d 728, 733
(4th Cir. 1990), we cannot conclude that the Sixth Amendment pro-
vides an unconditional right to a twelve-person jury in federal court.5

   Significantly, however, neither the Supreme Court nor any federal
appellate court has resolved whether the Due Process Clause permits
the arbitrary deprivation of a defendant’s right, guaranteed by Rule
23(b), to a twelve-person jury. Given the critical importance of twelve
jurors at common law and Congress’s particular care in Rule 23(b) to
preserve that right, except in carefully limited circumstances, such a
holding seems not unlikely. Indeed, in holding that Rule 31(a)’s jury
unanimity requirement is constitutionally mandated, the Supreme
  5
    We note, however, that the Supreme Court has never held that the
Sixth Amendment does not require a twelve-person jury in federal prose-
cutions, and several members of the Court have rejected the view that
"all elements of jury trial within the meaning of the Sixth Amendment
are necessarily embodied in or incorporated into the Due Process Clause
of the Fourteenth Amendment." Johnson v. Louisiana, 406 U.S. 356, 369
(1972) (Powell, J., concurring in that case and Apodaca v. Oregon, 406
U.S. 404 (1972)); see Ballew v. Georgia, 435 U.S. 223, 246 (1978)
(Powell, J., concurring in judgment and joined by Burger, C.J., and
Rehnquist, J.) (suggesting — in case involving the size of state court jury
— that not "every feature of jury trial practice must be the same in both
federal and state courts"). This has led Professor Wright to note that "it
may well be that in federal court a jury of [12] is still constitutionally
compelled." 2 Charles Alan Wright, Federal Practice & Procedure
§ 373, at 457 (3d ed. 2000). In addition, we note that many state constitu-
tions contain a specific guarantee to twelve-person juries, obviating any
need for a Sixth Amendment guarantee of this right in those states. See,
e.g., State v. Henley, 687 P.2d 1220, 1223 (Ariz. 1984) (Arizona); Byrd
v. State 879 S.W.2d 435, 437 (Ark. 1994) (Arkansas); State v. Poindex-
ter, 545 S.E.2d 414, 416 (N.C. 2001) (North Carolina); State v. Stegall,
881 P.2d 979, 981-82 (Wash. 1994) (Washington); State v. Wyndham, 92
S.E. 687, 687 (W. Va. 1917) (West Virginia).
10                     UNITED STATES v. CURBELO
Court has indicated that the right to a unanimous jury "is more accu-
rately characterized as a due process right than as one under the Sixth
Amendment." Schad v. Arizona, 501 U.S. 624, 634 n.5 (1991) (plural-
ity opinion); see also Apodaca v. Oregon, 406 U.S. 404 (1972) (hold-
ing that defendant has constitutional right to unanimous jury verdict
in federal court). Moreover, the Court has held that violations of state
procedural rules can amount to violations of an individual’s
constitutionally-guaranteed right to due process. For example, in
Hicks v. Oklahoma, 447 U.S. 343 (1980), the Court held that a state
sentencing decision violated due process when the jury that imposed
the sentence was not informed of its discretion, under state law, to
impose a lower sentence. Id. at 346. According to the Court, this sen-
tencing decision involved more than "the denial of a procedural right
of exclusively state concern"; it was a violation of the fundamental
right to due process. Id. Similarly, in Logan v. Zimmerman Brush Co.,
455 U.S. 422 (1982), when a state denied a hearing to a complainant
solely because a state official missed a state law deadline, the Court
held the denial violated the complainant’s due process rights. Id. at
432-34.

    Fortunately, we need not resolve the knotty question of whether the
error here is of constitutional dimension. This is so because, even if
it is not, we must, for two independent reasons, vacate Curbelo’s sen-
tence. We discuss each in turn.

                                   III.

   First, whether violative of the Constitution or not, the error here is
structural, and such errors "invalidate the conviction" without any
showing of prejudice. Sullivan, 508 U.S. at 279.6
  6
   Despite occasionally suggesting in dicta that structural errors must
implicate constitutional rights, see United States v. Lane, 474 U.S. 438,
446 n.9 (1986), the Supreme Court has clearly held that structural errors
need not be of constitutional dimension. Indeed, the Court reached pre-
cisely this conclusion only a few months ago. See Nguyen v. United
States, 123 S. Ct. 2130, 2137 (2003) (refusing to consider constitutional
challenge and holding that violation of statute alone constituted plain
error, requiring invalidation of conviction without showing of prejudice);
see also Gomez v. United States, 490 U.S. 858, 876 (1989) (holding that
                       UNITED STATES v. CURBELO                          11
   Structural errors affect the very "‘framework within which the trial
proceeds, rather than simply . . . the trial process itself.’" Neder v.
United States, 527 U.S. 1, 8 (1999) (quoting Fulminante, 499 U.S. at
310). Examples of such errors include a total deprivation of the right
to counsel, see Gideon v. Wainwright, 372 U.S. 335 (1963), lack of
an impartial trial judge, see Tumey v. Ohio, 273 U.S. 510 (1927), an
unlawful exclusion of grand jurors of defendant’s race, see Vasquez
v. Hillery, 474 U.S. 254 (1986), the right to self-representation at trial,
see McKaskle v. Wiggins, 465 U.S. 168 (1984), the right to a public
trial, see Waller v. Georgia, 467 U.S. 39 (1984), an erroneous
reasonable-doubt instruction to the jury, see Sullivan v. Louisiana,
508 U.S. 275 (1993), and the seating of a juror who should have been
removed for cause, see United States v. Martinez-Salazar, 528 U.S.
304, 316 (2000); see also Neder, 527 U.S. at 8 (collecting structural
error cases (citing Johnson v. United States, 520 U.S. 461, 468-69
(1997))). It is because such errors "‘infect the entire trial process’"
that they require reversal without regard to the evidence in a particu-
lar case. Neder, 527 U.S. at 8 (quoting Brecht v. Abrahamson, 507
U.S. 619, 630 (1993)). The error here — depriving a defendant of the

violation of statute governing duties of federal magistrate judges required
reversal without regard to actual prejudice); Young v. United States, 481
U.S. 787 (1987) (plurality opinion) (holding violation of right to disinter-
ested prosecutor fundamental and avoiding constitutional issue; utilizing
instead Court’s supervisory authority to reverse); United States v.
American-Foreign S.S. Corp., 363 U.S. 685, 691 (1960) (holding that
violation of statute governing en banc participation of circuit judges
required judgment to be vacated without showing of prejudice). Contrary
to our dissenting colleague’s suggestion, post at 25, these cases do not
involve jurisdictional issues; indeed, the Government specifically recog-
nized that the error in Nguyen was not jurisdictional. See Brief for the
United States in Nguyen v. United States, 123 S. Ct. 2130 (2003). Nor,
notwithstanding the dissent’s contention, has the Supreme Court ever
held that "structural errors necessarily must affect a defendant’s constitu-
tional rights." Post at 23. The decisions relied on by the dissent for this
proposition, post at 23-24, merely hold that not every constitutional error
is a structural error; none holds that a structural error need be premised
on a constitutional deprivation.
12                     UNITED STATES v. CURBELO
verdict of twelve jurors, without his consent or any finding of good
cause — is such an error.7

   Like other structural errors, the error here has repercussions that are
"necessarily unquantifiable and indeterminate." Sullivan, 508 U.S. at
282. This is particularly true given the rules of evidence and the
restrictions that they quite legitimately place on any inquiry into jury
deliberations. See generally Tanner v. United States, 483 U.S. 107
(1987). We simply cannot know what affect a twelfth juror might
have had on jury deliberations. Attempting to determine this would
involve pure speculation.

   To be sure, we could review the trial transcript, weigh the relative
credibility of witnesses ourselves, and make an independent assess-
ment of Curbelo’s guilt. However, the Supreme Court has repeatedly
instructed that such determinations are exclusively reserved in our
system of justice for the jury, and are not to be undertaken by an
appellate court. See Sullivan, 508 U.S. at 281 ("[Where a] reviewing
court can only engage in pure speculation — its view of what a rea-
sonable jury would have done . . . , ‘the wrong entity judge[s] the
defendant guilty.’" (second alteration in original) (quoting Rose v.
Clark, 478 U.S. 570, 578 (1986)); Bollenbach v. United States, 326
U.S. 607, 615 (1946) ("In view of the place of importance that trial
by jury has in our Bill of Rights, it is not to be supposed that Congress
[in enacting the harmless error statute] intended to substitute the
belief of appellate judges in the guilt of an accused, however . . . justi-
fiably engendered by the dead record, for ascertainment of guilt by a
  7
    The jury error in this case is easily distinguishable from the error in
United States v. Olano, 507 U.S. 725 (1993), which the Court held
should be evaluated for its prejudicial impact. See id. at 739-40 (applying
harmless error analysis where alternate jurors had improperly been
allowed in jury room); see also United States v. Myers, 280 F.3d 407,
412 (4th Cir.) (requiring defendant to demonstrate prejudice for violation
of Rule 24(c) to be reversible), cert. denied, 123 S. Ct. 53 (2002). In
Olano, the trial court erroneously permitted alternate jurors to be present
during jury deliberations. In such circumstances, it would be possible to
ascertain whether a defendant was prejudiced by the error. In this case,
by contrast, we can never know if the improperly-dismissed juror would
have voted to acquit.
                      UNITED STATES v. CURBELO                        13
jury under appropriate judicial guidance, however cumbersome that
process may be.").

   The Court has recognized that when an error "involves a violation
of a statutory provision that ‘embodies a strong policy concerning the
proper administration of judicial business,’" courts may vacate the
judgment without assessing prejudice. Nguyen v. United States, 123
S. Ct. 2130, 2138 (2003) (quoting Glidden Co. v. Zdanok, 370 U.S.
530, 536 (1962) (plurality decision)). Thus, while there is a "strong
presumption that" when counseled defendants have had their case
resolved by an impartial adjudicator, "other errors that may have
occurred are subject to harmless-error analysis," Rose, 478 U.S. at
579, the adjudicators themselves must be properly authorized and
constituted. When they are not, even if impartiality is not at issue, the
judgment must be vacated. See id. (observing that harmless error
review does not apply where "the wrong entity judged the defendant
guilty"); see also Nguyen, 123 S. Ct. at 2138; Gomez v. United States,
490 U.S. 858, 876 (1989); United States v. American-Foreign S.S.
Corp., 363 U.S. 685, 691 (1960).

   In Nguyen, for example, the Court vacated a decision by the Ninth
Circuit that had been rendered by a panel consisting of two Article III
judges and the Chief Judge of an Article IV territorial court. 123
S. Ct. at 2132-34. The Court held that Congress had not authorized
Article IV judges to serve on the courts of appeals, and that the Chief
Judge of the District for Northern Mariana Islands should not have
been permitted to serve on the Ninth Circuit panel. Id. at 2135.
Though urged by the Government to assess the prejudicial impact of
the error, the Court explicitly declined to do so, noting that when an
"error . . . involves a violation of a statutory provision that ‘embodies
a strong policy concerning the proper administration of judicial busi-
ness,’" id. at 2137-38 (quoting Glidden, 370 U.S. at 536), courts need
not "assess trial errors for their prejudicial effect." Id. at 2137.

   In Gomez, the Court also declined to apply a harmless-error analy-
sis to a violation of congressional policy regarding the proper adjudi-
cator in federal court. 490 U.S. at 876. There, the district court had,
without the defendant’s consent, allowed a magistrate judge to preside
over jury selection in a felony criminal trial. Id. at 860-61. The Court
decided that the Federal Magistrates Act did not authorize such a del-
14                     UNITED STATES v. CURBELO
egation. Importantly for our purposes here, the "defendants made no
special claim of prejudice. They contended . . . that the Magistrate had
no power to conduct the voir dire examination and jury selection." Id.
at 861. Although the Government urged the Court to apply harmless
error review, the Court refused, observing that "[a]mong those basic
fair trial rights that ‘can never be treated as harmless’ is . . . a defen-
dant’s right to have all critical stages of a criminal trial conducted by
a person with jurisdiction to preside." Id. at 876 (quoting Chapman,
386 U.S. at 23).

   Similarly, in American-Foreign, the Court refused to review for
prejudice a decision rendered by an improperly constituted en banc
court. 363 U.S. at 691. In that case, a retired circuit judge had partici-
pated in an en banc decision of a circuit court. The Supreme Court
held that the relevant federal statute did not authorize retired judges
to participate in such a proceeding. Id. at 686, 691. Thus, the Court
held that "under existing legislation a retired circuit judge is without
power to participate in an en banc Court of Appeals determination,
and accordingly that the judgment must be set aside." Id. at 691.
Despite the Government’s argument that the error was harmless, see
Brief for Respondents in American-Foreign at 37-47, the Court
declined to consider "the merits of the underlying litigation" in deter-
mining whether the judgment should be vacated. American-Foreign,
363 U.S. at 691.

   Just as the judgments rendered in those cases required vacatur
without regard to prejudice because the adjudicators lacked congres-
sional authorization, the judgment by the eleven-person jury in this
case must be set aside. Rule 23(b) has deep historical and constitu-
tional roots and indisputably represents a "strong policy," Nguyen,
123 S. Ct. at 2138, of ensuring criminal defendants in federal court
the right to a twelve-person jury. Moreover, under the clear provisions
of the Rule, the district court was "without power," American-
Foreign, 363 U.S. at 691, to dismiss one of the jurors prior to deliber-
ation, absent Curbelo’s consent. Consequently, the district court’s
action depriving Curbelo of his right to a twelve-person jury requires
us to vacate his convictions, without inquiry into specific prejudice
caused by the error. See United States v. Hanno, 21 F.3d 42, 48 (4th
Cir. 1994) (holding that, without regard to evidence of defendant’s
guilt, district court’s improper dismissal of jurors was prejudicial).
                       UNITED STATES v. CURBELO                        15
   Not surprisingly, all of our sister circuits, in considering violations
of Rule 23(b), have agreed that such violations require per se reversal
and are not subject to harmless error review.8 For example, in United
States v. Essex, 734 F.2d 832 (D.C. Cir. 1984), the Court of Appeals
for the District of Columbia vacated a defendant’s conviction because
a trial court excused a juror after deliberations had begun without
conducting a specific inquiry into whether dismissal was "necessary"
and for "just cause," as required by Rule 23(b). Id. at 834, 842.
Eschewing harmless error review, the court of appeals awarded Essex
a new trial, explaining that she had been denied "[t]he obvious and
substantial right . . . to a unanimous verdict by the jury of 12 who
heard her case and began their deliberations." Id. at 844 (emphases in
original).

  In doing so, the Essex court specifically held that the harmless error
analysis does not apply to violations of Rule 23(b). Id. at 845. The
court carefully analyzed and explained the reasons for excepting a
Rule 23(b) error from harmless error review:

      In cases involving secret jury deliberations it is virtually
      impossible for a defendant to demonstrate actual prejudice.
      Courts therefore have determined that the potential for seri-
      ous harm and the interest of the defendant — and the public
      — in fair, unbiased and secret deliberations are so great that
      no evidentiary showing of actual prejudice, or of defense
  8
    The only court to have suggested that a harmless error analysis might
apply is the Eighth Circuit, in United States v. Roby, 592 F.2d 406, 408
(8th Cir. 1979) (per curiam). In Roby, however, the Eighth Circuit
addressed a situation where the violation of Rule 23(b) was a technical
one: the defendant’s consent had been obtained orally, rather than in
writing. Id. In similar circumstances, most courts, including ours, refuse
to find a Rule 23(b) error, reasoning that a defendant has either waived
the writing requirement or invited the error. See, e.g., Fisher, 912 F.2d
at 731-33 (finding that defendant had waived Rule 23(b)’s written stipu-
lation requirement by orally consenting to eleven-person jury); see also,
e.g., United States v. Mahler, 141 F.3d 811, 814-15 (8th Cir. 1998)
(applying invited error doctrine in similar circumstances). The writing
requirement of Rule 23(b) is a technical aspect of the Rule, and oral con-
sent will, in most cases, satisfy the Rule’s stipulation requirement. The
Eighth Circuit’s per curiam decision in Roby stands for nothing more.
16                     UNITED STATES v. CURBELO
     counsel’s objection to the internal functioning of the jury of
     which he could not possibly be informed, is required.

Id. The D.C. Circuit reaffirmed this holding in United States v. Pat-
terson, 26 F.3d 1127 (D.C. Cir. 1994). There, as in Essex, the trial
court had excused a juror without making the requisite finding "that
it is ‘necessary’ to excuse the juror for ‘just cause.’" Id. at 1129. Rely-
ing on Essex, the court held that such an error is per se reversible,
without regard to whether the error prejudiced the defendant. Id.

   Similarly, in United States v. Taylor, 498 F.2d 390 (6th Cir. 1974)
(per curiam), the Sixth Circuit rejected the proposition that harmless
error review applies to a violation of Rule 23(b). Id. at 392. In Taylor,
the trial court had obtained an oral stipulation from defendant’s coun-
sel to proceed with eleven jurors if a juror became ill. Id. at 391. The
Sixth Circuit had previously held that an oral stipulation satisfied the
stipulation requirement of Rule 23(b). See United States v. Lane, 479
F.2d 1134 (6th Cir. 1973) (per curiam). The Taylor court, however,
found error in the trial court’s failure to question the defendant
directly on whether he consented to proceeding with eleven jurors.
Taylor, 498 F.2d at 391. Thus, the "sole question" presented on
appeal was "whether the failure of the District Court to comply liter-
ally with the terms of Rule 23 requires reversal for new trial." Id. at
392. Addressing this issue, the Sixth Circuit stated: "[w]e note that the
government’s primary insistence on this appeal is that the error com-
plained of was harmless. We cannot so construe it. To do so would
be to open the door to emasculation of the rule." Id.

   By the same token, the Seventh Circuit in United States v. Araujo,
62 F.3d 930 (7th Cir. 1995), recently decided that a violation of Rule
23(b) entitles a defendant to a new trial, without regard to whether the
error was actually prejudicial. Id. at 937. In Araujo, the court noted
that two distinct questions are presented by a trial court’s decision to
excuse a juror: "first, whether the court had just cause to excuse the
twelfth juror, and second, whether the district court was correct in
allowing the bobtailed jury to continue rather than declaring a mis-
trial." Id. at 933. The trial court had dismissed a juror who had "prob-
lems with his automobile," id. at 932, and "was stranded on the side
of the road." Id. (internal quotation marks omitted). The Seventh Cir-
cuit determined that these bases for dismissal failed to satisfy the "just
                       UNITED STATES v. CURBELO                          17
cause" requirement of Rule 23(b), and it reversed Araujo’s convic-
tions without reaching the second question. Id. at 934-37. Impor-
tantly, and particularly relevant here, the court awarded relief on the
Rule 23(b) error without considering whether Araujo suffered actual
prejudice. Id. at 937.

   Finally, the Ninth Circuit has also decided that a violation of Rule
23(b) entitles a defendant to a new trial — without regard to a show-
ing of actual prejudice. In United States v. Tabacca, 924 F.2d 906
(9th Cir. 1991), the court concluded that Rule 23(b) was violated
when a juror was excused because his wife had taken his car keys. Id.
at 913. Finding these facts insufficient to provide "just cause" to dis-
miss the juror, the court awarded Tabacca a new trial. Id. at 915.
Likewise, in United States v. Guerrero-Peralta, 446 F.2d 876 (9th
Cir. 1971), the Ninth Circuit premised its reversal of a defendant’s
convictions on a Rule 23(b) violation. In that situation, defense coun-
sel had orally represented to the trial court that the defendant agreed
to proceed with eleven jurors. Id. at 877. The court found that the oral
representation failed to satisfy Rule 23(b)’s mandate,9 and it reversed
without considering harmlessness. Id.; see also United States v.
Reyes, 603 F.2d 69, 71-72 (9th Cir. 1979) (declining to apply harm-
less error standard to violation of Rule 23(b)’s written stipulation
requirement).10

  In light of the fundamental importance of the jury in our criminal
  9
    Rule 23(b) requires a defendant’s stipulation to be in writing. See Fed.
R. Crim. P. 23(b)(2) (2002).
   10
      Our sister circuits have also held that violations of other Federal
Rules of Criminal Procedure are per se reversible. See, e.g., Green v.
United States, 262 F.3d 715, 717-18 (8th Cir. 2001) (holding violation
of Rule 8(c) of Rules Governing § 2255 Proceedings, which guarantees
right to counsel on habeas, required reversal without regard to prejudice);
United States v. Fawley, 137 F.3d 458, 470-71 (7th Cir. 1998) (holding
jury instruction that violated Rule 31(a) was reversible error without con-
sideration of prejudice); United States v. F. J. Vollmer & Co., Inc., 1
F.3d 1511, 1522 (7th Cir. 1993) (holding that "[t]he right to poll a jury
is a substantial right" guaranteed by Rule 31(d) and that "[f]ailure to poll
a jury upon a timely request is per se error requiring reversal" (internal
quotation marks omitted)).
18                      UNITED STATES v. CURBELO
justice system, Curbelo’s right to due process, and the express provi-
sion in the Federal Rules of Criminal Procedure governing the dis-
missal of a juror, we must follow our sister circuits and conclude that
the court’s decision to excuse the twelfth juror prior to deliberations
and absent the defendant’s consent falls into the special category of
errors that "defy analysis by harmless-error standards" and require
automatic reversal because they are "necessarily unquantifiable and
indeterminate." Sullivan, 508 U.S. at 281-82 (internal quotation marks
and citation omitted); see United States v. Neal, 101 F.3d 993, 999
(4th Cir. 1996) ("Errors that are not susceptible to harmless error
review . . . necessarily affect substantial rights." (internal quotation
marks and citation omitted)).

   The Rule 23(b) error in Curbelo’s trial tainted the process by which
guilt was determined, and it therefore inherently casts doubt on the
reliability of the jury’s verdict. It is this sort of error — like others
that have been deemed ill-suited to the harmless error inquiry, see,
e.g., Nguyen, 123 S. Ct. at 2138; Martinez-Salazar, 528 U.S. at 316;
Sullivan, 508 U.S. at 281-82; United States v. David, 83 F.3d 638,
647 (4th Cir. 1996) — that is inherently prejudicial and per se revers-
ible. As the D.C. Circuit explained in Essex, in assessing a similar
Rule 23(b) violation, "where, as here, the prejudice is inherent in the
error complained of, the defendant is not required to prove that he is
innocent, or that the outcome of the trial would have been different."
734 F.2d at 845. Accordingly, "even defendants who are obviously
guilty are entitled to the basic procedural safeguards of a fair trial,"
including those required by Rule 23(b). Id.11
  11
    The dissent’s effort to distinguish Essex and the other Rule 23(b)
decisions of our sister circuits misses the mark. The dissent maintains
that in those cases "the district court failed to establish sufficient ‘just
cause’ for excusing a juror," while in this case Curbelo does not assert
a failure to establish "just cause." Post at 29. Even if just cause is estab-
lished, however, Rule 23(b) permits a trial court to excuse a juror only
"after the jury has retired to consider its verdict." Fed. R. Crim. P. 23(b).
In the Rule 23(b) decisions of our sister circuits, the district courts at
least acted at the juncture permitted by the Rule — after jury delibera-
tions had commenced. Here the district court decided to proceed with
eleven jurors in the midst of trial, well prior to jury deliberations. Noth-
ing in the Rule permits such a procedure, no matter how "just" the cause.
                       UNITED STATES v. CURBELO                         19
                                   IV.

   Even if we were to conclude that the district court’s violation of
Rule 23(b) — in improperly dismissing one of the jurors from Cur-
belo’s trial — did not constitute structural error and therefore was
subject to harmless error review, we would nonetheless be forced to
vacate Curbelo’s conviction. This is so because the Government has
failed to meet its burden of demonstrating that the error was harmless,
even if we assume the error is not of constitutional dimension and we
thus apply the harmless error standard announced by the Court in Kot-
teakos.

   If the defendant fails to raise an objection to an error at trial, we
review the error under the plain error standard of Rule 52(b). Under
that rule, the defendant bears the burden of demonstrating that a plain
error affected his substantial rights, and even if he meets this burden,
an appellate court has discretion to ignore the error and should do so
unless it "seriously affect[s] the fairness, integrity or public reputation
of judicial proceedings." Olano, 507 U.S. at 732 (internal quotation
marks omitted and alteration in original). In contrast, if a defendant
preserves his objection to an error, an appellate court reviews the
error under the harmless error standard of Rule 52(a) — a standard
significantly more favorable to the defendant. Under Rule 52(a), the
Government bears the burden of demonstrating that the error did not
affect the defendant’s substantial rights. If the Government fails to
meet that burden, an appellate court must reverse; it has no discretion
to ignore the error. Id. at 734-35. The Government concedes that Cur-
belo preserved his objection to the error here and that (if the error
were not structural) our review is under the more-favorable-to-the-
defendant standard of Rule 52(a), with the Government bearing the
burden of proving the error did not affect Curbelo’s substantial rights.

   In its landmark decision in Kotteakos, the Supreme Court explained
that when reviewing a nonconstitutional error under Rule 52(a), an
appellate court must determine if the Government has proved "with
fair assurance . . . that the judgment was not substantially swayed by
the error." 328 U.S. at 765. Moreover, in determining if the Govern-
ment has met this burden, a court must not "strip[ ] the erroneous
action from the whole." Id. Thus,
20                    UNITED STATES v. CURBELO
     [t]he inquiry cannot be merely whether there was enough
     [evidence] to support the result, apart from the phase
     affected by the error. It is rather, even so, whether the error
     itself had substantial influence. If so, or if one is left in
     grave doubt, the conviction cannot stand.

Id. The Court later explained that "grave doubt" meant "that, in the
judge’s mind, the matter is so evenly balanced that he feels himself
in virtual equipoise as to the harmlessness of the error." O’Neal v.
McAninch, 513 U.S. 432, 435 (1995).

  The Government maintains that the conceded Rule 23(b) error here
was harmless, but its entire argument as to harmlessness is as follows:

     There is no reason to believe that the verdict of a twelve-
     member jury would have been any different than the verdict
     of the eleven-member jury. Evidence of Defendant’s
     involvement in the drug conspiracy and evidence of Defen-
     dant’s participation in a series of drug deals was quite sim-
     ply overwhelming. Because Defendant’s substantial rights
     were not impaired, the verdict should be affirmed.

Brief of Appellee at 7. The Government does not in any way detail
the assertedly "simply overwhelming" evidence.

   This is, perhaps, for good reason. Although our careful review of
the record indicates that the Government presented substantial evi-
dence against Curbelo, the Government’s case was not "simply over-
whelming." Indeed, we cannot say with any assurance, let alone "fair
assurance" that the absence of a twelfth juror did "not substantially
sway[ ]" the judgment. Kotteakos, 328 U.S. at 765. Accordingly, we
cannot conclude that the Government has met its burden of demon-
strating that the jury’s decision was unaffected by the absence of the
twelfth juror.

   As an initial matter, we note that the Government charged Curbelo
with twelve crimes and that the eleven-person jury acquitted him of
five of them. The same witnesses testified as to all of the counts, i.e.,
both those on which the jury acquitted, as well as those on which it
                       UNITED STATES v. CURBELO                        21
convicted. This certainly indicates that a reasonable twelfth juror
could have found the Government’s evidence lacking (as the remain-
ing eleven did for some counts).

   Indeed, the district court itself found Williams, the principal Gov-
ernment witness, less than truthful; surely, a reasonable juror could
have as well. A juror could have concluded that Williams lied not
only about his role in Wendy’s kidnaping and the robbery but also
about his drug deals with Curbelo. Certainly when Williams became
the target of a federal investigation, he had every reason to lie about
his dealings with Curbelo.

   Furthermore, Williams himself admitted that there was "no physi-
cal evidence of any of th[e] transactions" in which he purportedly
engaged with Curbelo. Law enforcement officers also acknowledged
this and the limitations of the tapes that purportedly recorded the
transactions. Except for the agents, who could only testify about what
Williams and others told them and what the arguably-inconclusive
tapes revealed, all of the witnesses against Curbelo were co-
conspirators or drug dealers. Many of them had cooperation agree-
ments with the Government, and hence, a motive to lie.

   Perhaps most significantly, a juror could conclude that Jose, rather
than Curbelo, had sold drugs to Williams. After all, Curbelo rarely
spoke directly to Williams. Indeed, for many of the transactions, Wil-
liams spoke only to Jose, gave money only to Jose, and took drugs
only from Jose. Thus, the jury was provided with a possible answer
to the critical question that arises in almost every criminal case: If the
defendant did not commit the crime, who did? It is undisputed that
Curbelo had little grasp of English. This gives some credence to Cur-
belo’s testimony that, because of the language barrier, he had no idea
that Williams and Jose were dealing drugs.

   Finally, Curbelo took the stand in his own defense and maintained
his innocence with detailed explanations of his non-drug-related rela-
tionships with the various witnesses. In light of the questionable cred-
ibility of many Government witnesses, the concessions of the law
enforcement officers who testified for the prosecution, Curbelo’s own
testimony, and the problems with the audio and video tapes, a twelfth
juror might easily have been left with reasonable doubt as to Cur-
22                    UNITED STATES v. CURBELO
belo’s guilt. Further, a twelfth juror might, during the course of jury
deliberations, have been able to raise persuasive points in Curbelo’s
defense; the juror may even have held out for acquittal on all counts.
Just as we recognized in Myers, 280 F.3d at 412, that the presence of
an additional juror made a guilty verdict less likely, we must
acknowledge in this case that the absence of a juror made a guilty
verdict more likely.

   For all of these reasons, even if the Rule 23(b) error were not struc-
tural, we would nonetheless conclude that Curbelo is entitled to a new
trial because the Government has failed to meet its burden to demon-
strate that the error was harmless. To be sure, the Government offered
"enough to support the result," but we have no "fair assurance . . . that
the judgment was not substantially swayed by the error." Kotteakos,
328 U.S. at 765. Thus even if the error were subject to harmless error
review, we could not conclude that it was sufficiently harmless to jus-
tify affirming Curbelo’s convictions.

                                   V.

  For the foregoing reasons, we vacate Curbelo’s convictions and
remand for a new trial.

                                        VACATED AND REMANDED

WILKINS, Chief Judge, dissenting:

   The majority concludes that the decision by the district court to
proceed with 11 jurors without Curbelo’s consent is a structural error
that mandates reversal without any inquiry into whether the error
actually prejudiced Curbelo. Alternatively, the majority concludes
that the error was not harmless because the evidence was sufficiently
close that the absence of a twelfth juror may have affected the verdict.
Because I disagree with both of these conclusions, I respectfully dis-
sent.

                                   I.

   Most errors that are preserved at trial—including most constitu-
tional errors—must be reviewed for harmlessness. See Fed. R. Crim.
                       UNITED STATES v. CURBELO                         23
P. 52(a) (providing that "[a]ny error, defect, irregularity, or variance
that does not affect substantial rights must be disregarded"); Neder v.
United States, 527 U.S. 1, 7 (1999). The Supreme Court, however,
has "recognized a limited class of fundamental constitutional errors
that defy analysis by harmless error standards." Neder, 527 U.S. at 7
(internal quotation marks omitted). "Errors of this type are so intrinsi-
cally harmful as to require automatic reversal (i.e., ‘affect substantial
rights’) without regard to their effect on the outcome." Id. Such errors
include the complete deprivation of counsel, a biased trial judge,
racial discrimination in the selection of a grand jury, or a defective
reasonable doubt instruction. See id. at 8 (collecting cases). These
errors are always reversible because they "deprive defendants of basic
protections without which a criminal trial cannot reliably serve its
function as a vehicle for determination of guilt or innocence and no
criminal punishment may be regarded as fundamentally fair." Id. at 8-
9 (internal quotation marks and alteration omitted).

   The majority’s determination that the error here is structural—and
thus not subject to harmless error review—is incorrect for two rea-
sons. First, this error cannot be structural because it is not of constitu-
tional magnitude. Second, even if the error were of constitutional
dimension, it would not qualify as a structural error because it did not
render the trial inherently unreliable or unfair.

                                    A.

   The Supreme Court and this court have repeatedly made clear that
structural errors necessarily must affect a defendant’s constitutional
rights. See, e.g., Neder, 527 U.S. at 7 ("Although [the harmless error
rule] by its terms applies to all errors where a proper objection is
made at trial, we have recognized a limited class of fundamental con-
stitutional errors that defy analysis by harmless error standards."
(second emphasis added) (internal quotation marks omitted)); Rose v.
Clark, 478 U.S. 570, 577 (1986) ("[T]he Court in Chapman recog-
nized that some constitutional errors require reversal without regard
to the evidence in the particular case." (emphasis added)); Arnold v.
Evatt, 113 F.3d 1352, 1360 (4th Cir. 1997) ("In examining the effect
of constitutional errors on criminal convictions, the Supreme Court
has established a distinction between structural errors, which require
automatic reversal, and all other errors, which are subject to harmless-
24                     UNITED STATES v. CURBELO
error analysis." (emphasis added)). As other circuits have recognized,
"[t]here is no separate category of structural error apart from constitu-
tional error. The only question is whether any constitutional errors . . .
rise to the level of structural error." United States v. Sanchez, 269
F.3d 1250, 1272 n.41 (11th Cir. 2001) (en banc), cert. denied, 535
U.S. 942 (2002); see also Ross v. United States, 289 F.3d 677, 681
(11th Cir. 2002) (per curiam) ("Structural error, to which harmless
error analysis does not apply, occurs only with extreme deprivations
of constitutional rights . . . ." (emphasis added) (internal quotation
marks omitted)), cert. denied, 537 U.S. 1113 (2003); Bentley v.
Scully, 41 F.3d 818, 823 n.1 (2d Cir. 1994) ("A ‘structural error’
requires automatic reversal and is not subject to harmless error analy-
sis because it involves a deprivation of a [basic] constitutional protec-
tion . . . ." (emphasis added)); United States v. Pavelko, 992 F.2d 32,
35 (3d Cir. 1993) ("‘Structural defects’ deprive the criminal trial of
constitutional protections . . . ." (emphasis added)).

   Yet the error that the majority classifies as structural—the decision
by the district court to proceed with 11 jurors absent Curbelo’s
consent—does not implicate Curbelo’s constitutional rights. In Wil-
liams v. Florida, 399 U.S. 78 (1970), the Supreme Court held that
criminal defendants have no Sixth Amendment right to a 12-person
jury. See Williams, 399 U.S. at 98-103. The majority suggests that the
holding of Williams may be limited to state court prosecutions and
that there may be a due process right to a 12-member jury. However,
in another case involving Federal Rule of Criminal Procedure 23(b),
we relied on Williams in recognizing that a defendant’s "constitu-
tional right to [a] jury trial . . . does not include the right to a jury of
twelve." United States v. Fisher, 912 F.2d 728, 733 (4th Cir. 1990)
(citing Williams, 399 U.S. at 98-103). And, other circuits have inter-
preted Williams as establishing that criminal defendants have no con-
stitutional right to 12 jurors. See, e.g., United States v. Barone, 114
F.3d 1284, 1308 n.21 (1st Cir. 1997) ("The Supreme Court has made
clear that the Constitution does not require twelve jurors for convic-
tion. We have stated that Williams effectively answers the claim that
11 jurors are too few . . . ." (citation and internal quotation marks
omitted)); United States v. Smith, 789 F.2d 196, 205 (3d Cir. 1986)
("It is clear to us that twelve jurors are not [constitutionally] required
for a conviction."); United States v. Stratton, 779 F.2d 820, 831 (2d
                        UNITED STATES v. CURBELO                           25
Cir. 1985) ("[T]he Supreme Court has . . . made clear that the Consti-
tution does not require twelve jurors for conviction.").

   The Supreme Court decisions cited by the majority do not support
the proposition that "structural errors need not be of constitutional
dimension." Ante, at 10 n.6. Most of those cases involve jurisdictional
errors, not structural ones. See, e.g., Nguyen v. United States, 123
S. Ct. 2130, 2132 (2003) (vacating judgments of court of appeals
because panel consisting of two Article III judges and one Article IV
judge did not "ha[ve] the authority to decide petitioners’ appeals"). In
contrast to structural errors, which involve inherent prejudice to a par-
ticular defendant, see Neder, 527 U.S. at 7-9, the cases cited by the
majority deal with errors primarily affecting the structure and func-
tion of the judicial system. See Nguyen, 123 S. Ct. at 2137 ("[O]ur
enforcement of [the designation statute’s] outer bounds is not driven
so much by concern for the validity of petitioners’ convictions at trial
but for the validity of the composition of the Court of Appeals."); id.
("Even if the parties had expressly stipulated to the participation of
a non-Article III judge in the consideration of their appeals . . . such
a stipulation would not have cured the plain defect in the composition
of the panel." (emphasis omitted)); United States v. American-
Foreign S.S. Corp., 363 U.S. 685, 691 (1960) (vacating en banc court
of appeals decision because retired circuit judge was "without power
to participate" in that decision, and "intimat[ing] no view as to the
merits of the underlying litigation").1 In each of these cases, the
  1
   One of the decisions cited by the majority includes language describ-
ing the jurisdictional error in terms of prejudice to the defendant. See
Gomez v. United States, 490 U.S. 858, 876 (1989) (referring to a defen-
dant’s "basic . . . right to have all critical stages of a criminal trial con-
ducted by a person with jurisdiction to preside"). But to the extent that
Gomez construes a magistrate judge’s involvement in jury selection in a
felony trial without the defendant’s consent as a structural error, that
error is based on a violation of the defendant’s constitutional right to
have an Article III judge preside over critical stages of trial. See Peretz
v. United States, 501 U.S. 923, 929-30 (1991); United States v. Arnoldt,
947 F.2d 1120, 1123 (4th Cir. 1991). Thus, Gomez does not support the
majority’s assertion that structural errors need not be constitutional in
nature. And, as explained above, a defendant has no constitutional right
to conviction by 12 jurors.
26                     UNITED STATES v. CURBELO
Supreme Court invalidated judicial proceedings involving judges who
lacked the power to participate in those proceedings. These decisions
are inapplicable to this case involving a violation of a procedural rule
during trial by a district judge who unquestionably had jurisdiction to
preside over the case. Indeed, I have found no decision—and the
majority has cited none—applying these holdings to trial errors
involving the composition of juries.

   The majority claims that the error here, like the error in Nguyen,
"involves a violation of a statutory provision that ‘embodies a strong
policy concerning the proper administration of judicial business’" and
therefore should not be reviewed for harmlessness. Nguyen, 123 S. Ct.
at 2137-38 (quoting Glidden Co. v. Zdanok, 370 U.S. 530, 536 (1962)
(plurality opinion)). But again, both Nguyen and Glidden involved
jurisdictional issues concerning whether particular judges were
empowered to preside over certain proceedings. Thus, it is clear that
the language regarding "administration of judicial business," as used
by the Supreme Court, applies only to errors that primarily affect the
court system. See American-Foreign S.S. Corp., 363 U.S. at 687
(describing issue regarding power of retired circuit judge to partici-
pate in en banc decision as "a question of importance to the Court of
Appeals in the administration of their judicial business").

                                   B.

  Even if the error here were of constitutional magnitude, it would
not amount to structural error. The Supreme Court has recognized that

   The majority also cites Young v. United States ex rel. Vuitton et Fils
S.A., 481 U.S. 787 (1987). In Young, however, only four of the nine jus-
tices concluded that the appointment of an interested private attorney to
prosecute a criminal contempt action is per se reversible error because
of the inherent conflict of interest. See id. at 809-14 (Opinion of Bren-
nan, J.). Three other justices concluded that the error should be reviewed
for harmlessness. See id. at 826-27 (Powell, J., concurring in part and
dissenting in part). In any event, the error in Young—like the errors in
the other cases cited by the majority, and unlike the error here—affected
the proper functioning of the judicial system. Indeed, a majority of the
Court in Young agreed that the exercise of the Court’s supervisory
authority was appropriate because the case involved "the determination
of the procedures to be employed by courts to enforce their orders, a sub-
ject that directly concerns the functioning of the Judiciary." Id. at 809.
                      UNITED STATES v. CURBELO                        27
"most constitutional errors can be harmless." Neder, 527 U.S. at 8
(internal quotation marks omitted). "If the defendant had counsel and
was tried by an impartial adjudicator, there is a strong presumption
that any other constitutional errors that may have occurred are subject
to harmless-error analysis." Id. (internal quotation marks and alter-
ations omitted). As explained above, the Supreme Court has "found
an error to be structural, and thus subject to automatic reversal, only
in a very limited class of cases," such as those involving the complete
deprivation of counsel, a biased trial judge, racial discrimination in
the selection of a grand jury, or a defective reasonable doubt instruc-
tion. Id. (internal quotation marks omitted). These errors require
reversal without any specific showing of prejudice to the defendant
because they "necessarily render a criminal trial fundamentally unfair
or an unreliable vehicle for determining guilt or innocence." Id. at 9.

   But unlike the errors listed above—which, by their very nature,
create a powerful presumption that the defendant was prejudiced—an
error by a district court in proceeding with 11 jurors absent a defen-
dant’s consent does not automatically render the trial unreliable or
unfair. Rule 23(b) allows the parties to stipulate at the outset of trial
that the jury will consist of fewer than 12 members. The parties may
also stipulate to proceeding with fewer than 12 jurors in the event the
court finds it necessary to excuse one or more jurors after trial com-
mences. See Fed. R. Crim. P. 23(b) (amended Dec. 1, 2002). Further,
the court may proceed with 11 jurors—even without the parties’
consent—if the court finds it necessary to excuse a juror after deliber-
ations have begun. See id. Thus, Rule 23 contemplates that verdicts
will sometimes be rendered, as here, by 11 rather than 12 jurors.

   It is undisputed that the decision by the district court to proceed
with 11 jurors violated the terms of Rule 23(b) because Curbelo
declined to consent to an 11-person jury and deliberations had not yet
begun. But the majority fails to explain how these circumstances
alone make the verdict rendered by 11 jurors inherently unreliable or
unfair. Indeed, the Supreme Court has specifically rejected the notion
that a jury with fewer than 12 members is less reliable or less fair to
defendants. See Williams, 399 U.S. at 100-02.

   The majority does not address the reliability and fairness concerns
that the Supreme Court has made clear are at the heart of structural
28                     UNITED STATES v. CURBELO
error analysis. Instead, my colleagues emphasize that the error here
affected the entire trial and therefore its prejudicial effect cannot be
quantified. But this approach overlooks the critical point that the error
of proceeding with trial before 11 jurors without the defendant’s con-
sent "does not necessarily render a criminal trial fundamentally unfair
or an unreliable vehicle for determining guilt or innocence." Neder,
527 U.S. at 9. Indeed, under the majority’s analysis, any error that
arguably had some connection to the trial as a whole—regardless of
whether it affected the reliability or fairness of the trial—might be
deemed structural. Cf. United States v. Lane, 474 U.S. 438, 446-49
(1986) (holding that misjoinder of defendants for trial, in violation of
Federal Rule of Criminal Procedure 8(b), is reviewable for harmless-
ness, and rejecting argument that such an error is per se prejudicial).

   And, while the majority claims that the error here is not sufficiently
quantifiable to be analyzed for harmlessness, other courts have
reviewed similar errors to determine their prejudicial impact on the
defendant. See United States v. Ahmad, 974 F.2d 1163, 1165-66 (9th
Cir. 1992) (holding that any error in conducting Rule 23(b) confer-
ence in defendant’s absence was not plain error, in part because
"given the strength of the evidence against [the defendant], and the
swiftness with which the jury returned its verdict, there is no reason
to believe that the verdict would have been different if either [the
excused juror] had been on the jury, or a different jury had heard the
case"); United States v. Roby, 592 F.2d 406, 408 (8th Cir. 1979) (per
curiam) (holding that any violation of Rule 23(b) in failing to obtain
written stipulation to use of 11-member jury was harmless because
evidence against defendant was "very strong").2 Indeed, the Supreme
Court has made clear that even the complete omission of an element
of a crime from the jury charge may be reviewed for harmlessness.
See Neder, 527 U.S. at 10. In such a case, harmless error review is
  2
    While the majority suggests that Roby dealt with a purely technical
violation of Rule 23(b), the Eighth Circuit apparently assumed for pur-
poses of decision that the lack of a written stipulation rendered invalid
the defendant’s consent to proceed with 11 jurors. See Roby, 592 F.2d at
408. Nonetheless, the Eighth Circuit examined the record and determined
that any such error was harmless because "[t]he evidence . . . was very
strong" and "[t]here was no evidence to sustain appellant’s claim that she
was being framed." Id.
                       UNITED STATES v. CURBELO                          29
permitted even though the jury was never required to weigh the evi-
dence on the omitted element and therefore no juror found all the ele-
ments necessary for conviction. See id. Here, however, 11 jurors
received proper instructions on the offense elements, weighed all of
the evidence, and unanimously found Curbelo guilty.

   Also, the cases that the majority cites for the proposition that viola-
tions of Rule 23(b) are per se reversible error are inapplicable here.
In nearly all of these cases, the district court failed to establish suffi-
cient "just cause" for excusing a juror before proceeding with an 11-
member jury, as required by Rule 23(b). The appellate decisions over-
turning the verdicts in these cases reflect the importance of preventing
jurors—particularly those who might have "dissenting views"—from
simply "opt[ing] out at will." United States v. Essex, 734 F.2d 832,
841 (D.C. Cir. 1984). Here, however, Curbelo does not assert that the
reason articulated by the district court for excusing the juror—that she
was "suffering from irritable bowel syndrome and [was] totally
unable to function," J.A. 143—was insufficient to establish "just
cause" for her excusal, or that the juror may have "opted out" because
of her views on the merits of the case.3 Cf. United States v. Wilson,
894 F.2d 1245, 1250-51 (11th Cir. 1990) (distinguishing Essex on the
ground that district court in case at bar had established just cause for
excusing juror during deliberations, and noting that "the record does
not present even the slightest basis to believe that this juror was a
holdout juror or that the jury had reached any sort of impasse in its
deliberations").

  In sum, because the majority’s approach to structural error analysis
  3
   The majority notes that "[o]ur sister circuits have also held that viola-
tions of other Federal Rules of Criminal Procedure are per se reversible."
Ante, at 17 n.10. The Supreme Court, however, has rejected the notion
that violations of the Rules of Criminal Procedure can never be reviewed
for harmlessness. See Lane, 474 U.S. at 446 n.9 ("It is difficult to see any
logic in the argument that although the harmless-error rule may be appli-
cable to constitutional violations, it should not be applied to violations
of mere procedural rules."); see also id. at 448 n.11 (rejecting "a rule-by-
rule review establishing bright-line per se rules whether to conduct
harmless-error analysis" and explaining that "on its face, Rule 52(a)
admits of no broad exceptions to its applicability").
30                    UNITED STATES v. CURBELO
vitiates the strong presumption in favor of harmless error review, I
must dissent from the holding that the error here is structural. See
Neder, 527 U.S. at 18 ("Reversal for error, regardless of its effect on
the judgment, encourages litigants to abuse the judicial process and
bestirs the public to ridicule it." (internal quotation marks omitted));
see also Sherman v. Smith, 89 F.3d 1134, 1138 (4th Cir. 1996) (en
banc) (emphasizing that "judges should be wary of prescribing new
errors requiring automatic reversal" and that "before a court adds a
new error to the list of structural errors (and thereby requires the
reversal of every criminal conviction in which the error occurs), the
court must be certain that the error’s presence would render every
such trial unfair").

                                  II.

   Having concluded that the error by the district court in proceeding
with 11 jurors was not structural, I would further hold that this error
was harmless. The narcotics trafficking evidence against Curbelo was
"quite simply overwhelming." Br. of Appellee at 7. Though the
majority highlights what it perceives as weaknesses in the Govern-
ment’s evidence, the overall case against Curbelo on the narcotics
charges was extremely strong. This evidence included a number of
tape-recorded conversations among Curbelo and his associates dis-
cussing narcotics transactions; controlled purchases of narcotics from
Curbelo’s place of business; testimony from several individuals
describing Curbelo’s involvement in drug trafficking; warranted
searches of Curbelo’s real property and vehicle that yielded narcotics,
paraphernalia, and incriminating documents; and testimony from an
ATF agent describing an interview during which Curbelo—with his
attorney present—confessed in detail to drug trafficking.

   In response to this compelling evidence, Curbelo "den[ied] that
[he] was ever involved in drug transactions," J.A. 403; asserted that
all the Government’s witnesses were "lying," id. at 381; and claimed
that the surveillance tapes containing his voice had been "manipu-
lated," "edited," and "tampered with," id. at 408, 410. Curbelo also
testified that his conversations about narcotics were intended to create
the illusion of a "pretend simulated drug business" in order to "set a
trap" for Thurnell Williams, who Curbelo believed had previously
robbed his store. Id. at 394-95. However, Curbelo claimed that he was
                       UNITED STATES v. CURBELO                        31
later surprised to learn that one of his main associates who was also
part of these conversations was actually selling drugs to Williams.
Curbelo also denied making some of the statements to the ATF agent
and claimed that he had fabricated others to protect his girlfriend from
prosecution.

   In short, the Government presented a mountain of proof that Cur-
belo was guilty of narcotics trafficking. And, Curbelo’s complete
denial of guilt—relying on far-fetched explanations for the Govern-
ment’s evidence—does not create a reasonable doubt regarding
whether the twelfth juror’s absence affected the verdict. See, e.g.,
United States v. Blevins, 960 F.2d 1252, 1263-64 (4th Cir. 1992)
(holding that despite defendants’ testimony asserting their innocence,
admission of improper evidence was harmless error in light of over-
whelming evidence of defendants’ guilt). Also, while the record is not
entirely clear, it appears that the jury reached its verdict in a matter
of hours. Under these circumstances, I can say with more than "fair
assurance . . . that the judgment was not substantially swayed by the
error" of proceeding with 11 jurors. Kotteakos v. United States, 328
U.S. 750, 765 (1946).4

  4
    In asserting that a 12-member jury might have reached a different ver-
dict on the narcotics charges, the majority notes that the 11-member jury
acquitted Curbelo on the charges of possessing firearms in furtherance of
drug trafficking. But this argument overlooks the fact that the evidence
concerning the firearms charges was different from and much weaker
than the evidence on the narcotics charges. If anything, the fact that the
same 11-member jury that convicted Curbelo of all the narcotics charges
also acquitted him of the firearms charges demonstrates the reliability of
this jury in carefully weighing the evidence relating to each of the
charges.
  The majority also notes that the district court was skeptical of certain
aspects of Williams’ testimony. As explained above, however, the Gov-
ernment presented extensive evidence against Curbelo from sources
other than Williams. Thus, even independent of Williams’ testimony, the
Government presented a compelling case establishing Curbelo’s involve-
ment in drug trafficking.
32                    UNITED STATES v. CURBELO
                                  III.

   Despite the error by the district court in proceeding with 11 jurors,
Curbelo received what the Constitution entitles him to: "a fair trial,
not a perfect one." Rose, 478 U.S. at 579 (internal quotation marks
omitted). "‘[T]he commonsense judgment of a group of laymen . . .
large enough to promote group deliberation, free from outside
attempts at intimidation, and to provide a fair possibility for obtaining
a representative cross-section of the community’ was interposed
between [Curbelo] and his government accusers." Fisher, 912 F.2d at
733 (quoting Williams, 399 U.S. at 100) (first and second alterations
in original). And, Curbelo was convicted based on overwhelming evi-
dence, with no indication that the absence of a twelfth juror had any
effect on the verdict. I therefore dissent from the majority’s decision
to overturn the jury’s verdict based on a nonconstitutional error that
did not prejudice Curbelo. Because I believe that the other points
raised by Curbelo are also meritless, I would affirm his convictions
and sentences.
