                 FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,             
                Plaintiff-Appellee,          No. 08-10396
               v.                             D.C. No.
ABIMAEL ROBLERO-SOLIS,                    4:08-cr-00271-CKJ
             Defendant-Appellant.
                                      

UNITED STATES OF AMERICA,             
                Plaintiff-Appellee,          No. 08-10397
               v.                             D.C. No.
JANET ROBLERO-PEREZ,                      4:08-cr-00272-CKJ
             Defendant-Appellant.
                                      

UNITED STATES OF AMERICA,             
                Plaintiff-Appellee,         No. 08-10466
               v.                             D.C. No.
JORGE ROSALES-VARGAS,                     4:08-cr-00270-DCB
             Defendant-Appellant.
                                      

UNITED STATES OF AMERICA,             
                Plaintiff-Appellee,          No. 08-10509
               v.                             D.C. No.
MIGUEL ZARAZUA-PICHARDO,                  4:08-cr-00306-RCC
             Defendant-Appellant.
                                      

                           15697
15698            UNITED STATES v. ROBLERO-SOLIS



UNITED STATES OF AMERICA,                 
                Plaintiff-Appellee,              No. 08-10512
               v.                                 D.C. No.
JOSE VAZQUEZ-MORALES,                         4:08-cr-00312-RCC
             Defendant-Appellant.
                                          

UNITED STATES OF AMERICA,                       No. 08-10543
               Plaintiff-Appellant,                D.C. No.
               v.                              4:08-CR-00311-
GUMERCINDO MARTINEZ-CARRIZOSA,                       FRZ-1
            Defendant-Appellee.
                                                  OPINION


        Appeals from the United States District Court
                 for the District of Arizona
        Cindy K. Jorgenson, District Judge, Presiding
          David C. Bury, District Judge, Presiding
         Raner C. Collins, District Judge, Presiding
         Frank R. Zapata, District Judge, Presiding

                  Argued and Submitted
        November 2, 2009—San Francisco, California

                     Filed December 2, 2009

      Before: John T. Noonan and William A. Fletcher,
     Circuit Judges, and Thomas Duffy,* District Judge.

                   Opinion by Judge Noonan

   *The Honorable Kevin Thomas Duffy, United States District Judge for
the Southern District of New York, sitting by designation.
15700          UNITED STATES v. ROBLERO-SOLIS




                        COUNSEL

Jason Hannan, Assistant Federal Public Defender, Tucson,
Arizona, for the defendants-appellants-appellees.

Robert L. Miskell, Assistant United States Attorney, Tucson,
Arizona, for the plaintiff-appellee-appellant.
                UNITED STATES v. ROBLERO-SOLIS            15701
                          OPINION

NOONAN, Circuit Judge:

   To accommodate the enormous number of prosecutions for
illegal entry into the United States, the district court for the
District of Arizona (Tucson) has adopted a procedure for the
taking of pleas en masse intended to preserve the rudiments
of Fed. R. Crim. P. 11 and the constitution. We were informed
by the government in this case that one magistrate judge is
assigned each week full time to the handling of these cases
and that in twelve months’ time the court has handled 25,000.
The procedure has been in practice for at least two years and
is apparently followed in several other federal courts whose
districts border on Mexico.

   The problem generated by the massive caseload on the
court understandably led the court to adopt a shortcut.
Abstractly considered, the shortcut is not only understandable
but reasonable. The shortcut, however, does not comply with
Rule 11. We cannot permit this rule to be disregarded in the
name of efficiency nor to be violated because it is too
demanding for a district court to observe. We act within a sys-
tem maintained by the rules of procedure. We cannot dispense
with the rules without setting a precedent subversive of the
structure. Accordingly, on this challenge by an intrepid fed-
eral public defender to the Tucson court’s taking of pleas en
masse, we hold the procedure to be contrary to Rule 11. We
then assess the harm to the substantial rights of the six defen-
dants before us on this appeal.

                            FACTS

  Abimael Roblero-Solis (Roblero-S.), age about 19, a citizen
of Mexico, was apprehended by the United States Border
Patrol on March 3, 2008 inside of the United States without
documents authorizing his entry into the United States.
15702          UNITED STATES v. ROBLERO-SOLIS
   Janet Roblero-Perez (Roblero-P.), age about 19, is another
citizen of Mexico, apprehended on March 3, 2008 by the Bor-
der Patrol inside of the United States without documents.

   Jose Vasquez-Morales (Vasquez), about 26, is a citizen of
Mexico, also arrested on March 3, 2008 by the Border Patrol
inside of the United States without documents.

   Gumercindo Martinez-Carrizosa (Martinez), age about 26,
is another Mexican citizen without documents, arrested by the
Border Patrol on March 3, 2008 inside of the United States.

   Jorge Rosales-Vargas (Rosales), age about 24, is another
citizen of Mexico, apprehended without documents by the
Border Patrol inside of the United States, March 3, 2008.

   Miguel Zarazua-Pichardo (Zarazua), age about 29, is a citi-
zen of Mexico, also apprehended by the Border Patrol on
March 3, 2008 inside of the United States without documenta-
tion.

                      PROCEEDINGS

  March 5, 2008. Roblero-P, Robero-S, Martinez and
Vasquez appeared before Magistrate Judge Jennifer Guerin.
They were represented by Jason Hannan, Assistant Federal
Public Defender. Forty-three other defendants facing a similar
charge were present and had guilty pleas accepted. The pro-
ceedings in which they were participants are conveniently set
out by Tucson District Judge David G. Bury in one of the
decisions here on appeal:

    The Arizona Denial Prosecution Initiative (ADPI,
    a.k.a. Operation Streamline) is used by the United
    States Border Patrol to bring 50 to 100 people per
    day before a United States Magistrate Judge for an
    initial appearance to explain the charges against
    them and their rights, accept any guilty pleas, and
                UNITED STATES v. ROBLERO-SOLIS            15703
    sentence them. The proceedings before the Magis-
    trate Judge pertain to petty misdemeanor violations
    under 8 U.S.C. § 1325 for entering the country ille-
    gally and are conducted en masse, except for indi-
    vidually taking role and the actual guilty pleas.

   The court asked defense counsel if all of their clients “wish
to plead guilty this afternoon,” and the record reflects “gen-
eral ‘yes’ answers.” The court then asked if there was “any
objection to conducting these proceedings as a group.” Han-
nan stated:

    Your Honor, I would ask that the court determine
    that each of them has understood their rights, the fac-
    tual basis has been inquired of each of them individ-
    ually, and that each of them has an opportunity to
    speak, to be addressed by the court personally and to
    allocute to the court with defense counsel.

    THE COURT: So you have no objection to the
    group advisement is what I understand?

    HANNAN: Correct, as long as the court would
    inquire as to each individually if they understood
    their rights and the waiver (unintelligible).

    THE COURT: Thank you.

  The court advised defendants collectively of the procedure
which it intended to use to take the pleas as a group:

    THE COURT: I’m going to be advising you and
    informing you of your rights. If at any time you
    don’t understand what I’m saying or if you cannot
    hear me or hear the interpreter, I ask that you stand
    and that will give us the opportunity to make sure
    that the hearing apparatus is working correctly and
    also to clarify any questions that you might have. If
15704            UNITED STATES v. ROBLERO-SOLIS
    I direct a question to you as a group, then I ask that
    each one of you answers that question out loud
    loudly so that I can see and hear your response. If I
    cannot hear a response, then I will not be able to
    accept your guilty plea. Does everyone understand
    these directions?

The record reports a “General ‘yes’ response.”

   The court then advised the group of their rights to remain
silent and to be represented by an attorney and noted that each
defendant had an opportunity to meet with his attorney in the
morning. The court then asked anyone who did not know the
charges against him to stand. The court noted for the record
that “no one is standing.”

   The court advised the defendants of the consequences of
their plea. After each statement, the court asked defendants if
they understood, and each time the interpreter relayed a “Gen-
eral ‘yes’ response.” The court asked “If anyone has any
questions about what I’ve advised so far, please stand at this
time.” The court noted for the record that no one was stand-
ing.

   The court similarly advised defendants of their rights to a
trial and their rights at trial. After these advisements, the court
asked if the defendants understood “your right to have a trial
and what would be involved in that trial.” The interpreter con-
veyed a “General ‘yes’ response.” The court asked that any-
one who did not understand stand up. No one stood.

   The court asked if the defendants understood “that if you
plead guilty here this afternoon that there will be no trial.”
The interpreter conveyed another “General ‘yes’ response.”
However, the court paused here: “I’m not hearing everybody
respond to the question. So let me ask again to make sure that
everyone does understand that. Do you understand that if you
                UNITED STATES v. ROBLERO-SOLIS             15705
plead guilty here this afternoon that there will be no trial.”
The interpreter conveyed another “General ‘yes’ response.”

   Moving on, the court asked if the defendants understood
that by pleading guilty there would be no trial: “General ‘yes’
answer.” The court asked if anyone had forced or threatened
defendants to plead guilty: “General ‘no’ response.” The court
asked defendants if they were pleading guilty “voluntarily and
because you are guilty”: “General ‘yes’ response.”

  The court noted that those defendants who did not have a
written plea agreement (including all defendants appealing
here) had no plea agreement with the government. The court
asked if those defendants understood that the court “can
impose any sentence up to the maximum sentence that I
advised you of earlier”: “General ‘yes’ response.”

   The court then moved to the taking of the pleas. “Counsel”
the court asked, “do you believe that your clients are compe-
tent to plead guilty and that they are doing so voluntarily?”
“Counsel” gave “General ‘yes’ answers.” The court resumed
addressing the defendants, explained the elements of illegal
entry, and asked “Do each of you understand the charge of
illegal entry?” Again, “General ‘yes’ response.” The court
then asked anyone who did not understand the charge to
stand. The record does not show whether anyone stood.

   Now the court began to address defendants individually.
Each defendant was asked in turn “how do you plead to the
charge of illegal entry?” Each defendant responded, when cal-
led upon, “Guilty.”

   The court returned to addressing all defendants collectively
and asked them if they had committed each of the five ele-
ments of illegal entry. After each question, the court received
a “General ‘yes’ response” or a “General ‘no’ response” con-
sistent with guilt. After elements two and five, but not the oth-
ers, the court specifically asked defendants to stand if their
15706           UNITED STATES v. ROBLERO-SOLIS
answer was otherwise. The court noted for the record after
elements two and five that no one stood.

   The court returned to addressing counsel: “Mr. Hannan,
noting your objections, or just putting aside your objection for
a moment, counsel, are you satisfied with the factual basis for
the pleas with the exception of Mr. Hannan’s clients?” Coun-
sel gave “General ‘yes’ answers.” The government indicated
that it, too, was satisfied. The court asked whether there was
“any legal reason why the court should not accept the pleas.”
“Counsel” responded with “General ‘no’ answers.” The court
stated that it was accepting the pleas of all defendants.

   In the sentencing phase, the court sentenced en masse to
time served all defendants who did not have written plea
agreements.

   After sentencing, the court turned again to Hannan and his
clients specifically. This exchange followed:

    THE COURT: I want to make sure we have resolved
    all your concerns. If you want to have additional
    information on the record, we can do that and have
    your clients remain to do that.

    MR. HANNAN: Okay. I guess my objection,
    though, if I could just clarify to the court, was that
    the factual basis, the waiver of their rights would be
    addressed individually. They have already pled
    guilty and [been] sentenced. So I guess I’m not sure
    what there is to address.

    THE COURT: I think there’s two ways that it can be
    handled.

    You can withdraw any concerns that you might have
    about it or we can make sure that all of your con-
    cerns have been addressed and your defendants can
               UNITED STATES v. ROBLERO-SOLIS             15707
    remain in the courtroom and we will address those
    issues at this time to ensure there has been a factual
    basis that is satisfactory to you and that they have
    had every right to allocution that you think they
    might have been deprived of in this process.

    So I will leave that election to you.

    MR. HANNAN: I guess we will have them remain
    in courtroom. Thank you.

   The court addressed each defendant represented by Hannan
individually and asked whether he or she “underst[ood] that
by pleading guilty that you were giving up your right to have
a jury trial.” Each defendant responded “Yes.” The court then
asked each defendant individually what country he or she was
a citizen of. Each confirmed to the court that he or she was
a citizen of Mexico. The court then began addressing all of
the defendants represented by Hannan as a group. The court
asked, “Did anyone enter at a point of entry?” The interpreter
gave the defendants’ responses as “All ‘no.’ ” The court
asked, “Did any of you have official permission to be present
in the United States?”: “All ‘no.’ ” After asking Hannan if he
had anything further, the court ended the proceedings.

   March 6, 2008. Magistrate Judge Guerin took the pleas of
fifty defendants, including Rosales and Zarazua. Rosales and
Zarazua were represented by Hannan. Again, after taking roll
call, the magistrate judge asked if there were any objections
to conducting the proceedings as a group. Hannan objected
“to having the proceedings done in a group” as to Zarazua and
Rosales. Hannan explained the basis for his objection:

    Your Honor, the basis for the objections is that my
    clients in order to determine that the waiver is know-
    ing and voluntary requires an individualized assess-
    ment by the court. Additionally, as to the inquiry to
    the factual basis, in order to determine there is a fac-
15708           UNITED STATES v. ROBLERO-SOLIS
    tual basis (unintelligible). And, thirdly, the defendant
    has a right to allocute before the court personally as
    well as defense counsel addressed by the court. Both
    of my clients would like to do that.

In response, the magistrate judge questioned Hannan, asked
him if he had met with his clients, if he had advised them as
to their waiver, as to whether he thought that they understood
the waiver, as to whether he had any doubt of the factual basis
for each client’s offense, and as to whether he believed that
the pleas were voluntary. He answered that he had made the
advisements and that he had no doubt as to the factual basis
and waiver. Hannan did not object that the court was not
responding to his original objection. Neither the magistrate
judge nor Hannan returned to his objections for the rest of the
March 6 proceeding.

   After the colloquy regarding Hannan’s objections, the court
explained to the defendants the process that it would use to
take their pleas, including asking any defendant who did not
understand at any time to stand up. In the same fashion as it
had in the March 5 proceeding, the court proceeded to explain
defendants’ rights and ask whether defendants understood the
charges and the maximum penalty. In each case, the court
received “General ‘yes’ answers” as it had on March 5. As on
March 5, the court then addressed defendants one-by-one and
asked how each defendant pleaded. In each case, defendant
responded “Guilty.”

   To elicit the factual basis for these pleas, the magistrate
returned to addressing the defendants en masse. She asked the
defendants whether they disputed each element of the crime
and received “General ‘no’ answers” consistent with guilt. At
that time the court accepted the pleas of guilty and found that
the pleas were knowing, intelligent, and voluntary. Unlike
March 5, there was no post-plea colloquy with Hannan’s
defendants.
                UNITED STATES v. ROBLERO-SOLIS            15709
  Hearings in the District Court. Each of the six defendants
appealed his conviction by the magistrate judge to the district
court. Their appeals were assigned to four different district
judges.

   Each district court judge approached the cases somewhat
differently. Judge Cindy Jorgensen found that Roblero-S’s
and Roblero-P’s claims of error were not preserved and
reviewed their plea proceedings for plain error. Under this
standard, when the post-sentencing proceedings were taken
into account, Judge Jorgensen found that the magistrate did
not plainly err under the standards of Rule 11. Judge Jorgen-
sen also found that it was not error under the standards of due
process for the magistrate to take defendants’ pleas in a group
proceeding involving 47 defendants, because defendants were
represented by attorneys when their pleas were taken.

   Judge Raner Collins found that Hannan’s objections at the
outset of the proceedings were sufficient to preserve
Vasquez’s claims of Rule 11 error, and thus applied a de novo
standard of review to the Rule 11 claims. Nonetheless, look-
ing at the record as a whole, apparently including the post-
sentencing proceedings, Judge Collins found that the magis-
trate had produced a record that showed a factual basis to sat-
isfy Rule 11. As to due process, Judge Collins held that the
presence of counsel was sufficient.

   Judge Frank Zapata vacated the conviction of Martinez.
Judge Zapata found that Hannan had made his objection to the
factual basis for the plea clear to the court and that there was
no resolution of the objection before the court accepted the
plea, sentenced the defendant, and entered judgement on the
sentence. He also ruled that the post-sentencing colloquy was
insufficient to provide the Rule 11 factual basis and that the
error was not harmless.

  March 6 Cases. Judge Collins heard Zarazua’s case. He
found that Hannan’s March 6 objection was sufficient, and
15710           UNITED STATES v. ROBLERO-SOLIS
that the court’s choice to address Hannan to ask him as coun-
sel whether he believed that his clients were pleading guilty
voluntarily and upon a sufficient factual basis did not dispose
of the objection. Nonetheless, Judge Collins found that the
presence of counsel satisfied due process and that the magis-
trate had compiled a sufficient record to show that the plea
complied with Rule 11.

  Rosales had his appeal heard by Judge David Bury. Judge
Bury agreed with Judge Collins on every significant issue.

  Roblero-P, Roblero-S, Rosales, Vasquez and Zarazua
appeal the judgments of the district court. The government
appeals the judgment in Martinez’s case.

                          ANALYSIS

   [1] Mootness. Sua sponte this court raised the question of
whether the appeals were moot. The defendants have served
their sentences and apparently have been deported. They do
face the prospect of a higher sentence if they should again
make an illegal entry; but the possibility of “violating the law,
getting caught, and being convicted” does not constitute a
consequence preventing mootness. Spencer v. Kemna, 523
U.S. 1, 15 (1998). But they also face various adverse conse-
quences that will result even if they do not violate the law,
such as longer periods during which they will be ineligible to
enter legally. Further, in a case where constitutional rights
were allegedly at issue, the Supreme Court recognized that a
case was not moot when a state procedure cut off the possibil-
ity of appeal by the shortness of the sentence being appealed.
Sibron v. New York, 392 U.S. 42 (1968). Otherwise, it was
reasoned, short sentences could short circuit any appeal and
deprive defendants in “low visibility” cases of the chance of
vindicating their rights under the constitution. Id. at 52-53.
Although we do not reach a constitutional claim in this case,
we believe that analogous considerations counsel treating as
                UNITED STATES v. ROBLERO-SOLIS           15711
alive these cases where the “time served sentences” are so
short that no appeal would be practicable.

  Standard of review. The decisions of the district judges,
deciding questions of law, are reviewed de novo. See United
States v. Waites, 198 F.3d 1123, 1126 (9th Cir. 2000).

   The Requirements of Rule 11. Rule 11, in relevant part,
reads:

    (b) Considering and Accepting a Guilty or Nolo
    Contendere Plea.

    (1) Advising and Questioning the Defendant.

    Before the court accepts a plea of guilty or nolo con-
    tendere, the defendant may be placed under oath, and
    the court must address the defendant personally in
    open court. During this address, the court must
    inform the defendant of, and determine that the
    defendant understands, the following:

    (A) the government’s right, in a prosecution for per-
    jury or false statement, to use against the defendant
    any statement that the defendant gives under oath;

    (B) the right to plead not guilty, or having already so
    pleaded, to persist in that plea;

    (C) the right to a jury trial;

    (D) the right to be represented by counsel — and if
    necessary have the court appoint counsel — at trial
    and at every other stage of the proceeding;

    (E) the right at trial to confront and cross-examine
    adverse witnesses, to be protected from compelled
15712          UNITED STATES v. ROBLERO-SOLIS
    self-incrimination, to testify and present evidence,
    and to compel the attendance of witnesses;

    (F) the defendant’s waiver of these trial rights if the
    court accepts a plea of guilty or nolo contendere;

    (G) the nature of each charge to which the defendant
    is pleading;

    (H) any maximum possible penalty, including
    imprisonment, fine, and term of supervised release;

    (I) any mandatory minimum penalty;

    (J) any applicable forfeiture;

    (K) the court’s authority to order restitution;

    (L) the court’s obligation to impose a special assess-
    ment;

    (M) in determining a sentence, the court’s obligation
    to calculate the applicable sentencing-guideline
    range and to consider that range, possible departures
    under the Sentencing Guidelines, and other sentenc-
    ing factors under 18 U.S.C. § 3553(a); and

    (N) the terms of any plea-agreement provision waiv-
    ing the right to appeal or to collaterally attack the
    sentence.

    (2) Ensuring That a Plea Is Voluntary.

    Before accepting a plea of guilty or nolo contendere,
    the court must address the defendant personally in
    open court and determine that the plea is voluntary
    and did not result from force, threats, or promises
    (other than promises in a plea agreement).
                UNITED STATES v. ROBLERO-SOLIS           15713
    (3) Determining the Factual Basis for a Plea.

    Before entering judgment on a guilty plea, the court
    must determine that there is a factual basis for the
    plea.

   In its Notes on the 1966 Amendments to the Rules of Crim-
inal Procedure, the Advisory Committee had this to say about
the importance and role of Rule 11:

    The great majority of all defendants against whom
    indictments or informations are filed in the federal
    courts plead guilty. Only a comparatively small
    number go to trial. See United States Attorney Sta-
    tistical Reports, Fiscal Year 1964, p. 1. The fairness
    and adequacy of the procedures on acceptance of
    pleas of guilty are of vital importance in according
    equal justice to all in the federal courts.

It is in the light of these observations that we address the
claim that Rule 11 was violated.

    [2] Rule 11(b)(1) provides that before accepting a guilty
plea “the court must address the defendant personally in open
court.” During this address “the court must determine” that
the defendant understood certain specified rights, risks, and
consequences. Under section (b)(2) before accepting the
guilty plea, “the court must address the defendant personally
. . . and determine that the plea is voluntary.” Can these man-
datory requirements be met when the court addresses a multi-
tude of defendants?

   Answering affirmatively, the government has these argu-
ments: First, the adverb “personally” qualifies the action of
the judge. It is he who must act in person. Second, the Advi-
sory Committee Notes on the 1966 Amendments indicate that
the provisions on addressing the defendant “personally” were
made to assure that the judge addressed the defendant, not the
15714           UNITED STATES v. ROBLERO-SOLIS
defendant’s counsel. Third, out-of-circuit precedents show
that several defendants may be addressed together in a plea-
taking. See United States v. Martinez-Martinez, 69 F.3d 1215,
1223 (1st Cir. 1995); United States v. Hobson, 686 F.2d 628,
629-30 (8th Cir. 1981); United States v. Fels, 599 F.2d 142,
146 (7th Cir. 1979). The government concludes that “address
personally” requires less than “address individually.”

   [3] “Personally,” as an adverb, undoubtedly modifies the
verb “address”: the judge must act in person. But the adverb
also qualifies the nature of the judge’s speech: it must be to
a person, “in a personal manner,” as Webster’s Third Interna-
tional Dictionary (1986) defines “personally.” Indeed the
word order in which “personally” follows “the defendant”
emphasizes that the judge’s speech is to be person to person.
Persons occupy a central place in the Fourteenth Amendment.
“Person” and its derivative “personally” carry constitutional
connotations.

   [4] The rule speaks only of the defendant in the singular.
But the rules are not rigid. Fels involved three defendants
charged as co-conspirators. United States v. Fels, 599 F.2d at
144. Martinez-Martinez involved two defendants charged as
co-conspirators. United States v. Martinez-Martinez, 69 F.3d
at 1223. Hobson involved a small, if unspecified set of co-
defendants in the same conspiracy. United States v. Hobson,
686 F.2d at 626.

   [5] In contrast, nothing in the record in our case establishes
any connection between the defendants. The numbers are sig-
nificantly greater. These precedents do not establish a princi-
ple that the number of plea-takers may be indefinitely
expanded without violation of Rule 11.

   [6] To be specific, no judge, however alert, could tell
whether every single person in a group of 47 or 50 affirma-
tively answered her questions when the answers were taken at
the same time. No judge could have detected a mute response
                UNITED STATES v. ROBLERO-SOLIS            15715
offered in the midst of a medley of voices saying “Si.” No
judge, however conscientious, could have possessed the abil-
ity to hear distinctly and accurately fifty voices at the same
time. The record reflects the most that could be detected: a
“General Yes.” How different that record is from the hearing
in which four of the appellants were questioned together, and
the record reflects responses from “All.” Neither an indistinct
murmur or medley of yeses nor a presumption that all those
brought to court by the Border Patrol must have crossed the
border is sufficient to show that each defendant pleaded vol-
untarily.

   The errors do not constitute structural error as defined in
Arizona v. Fulminante, 499 U.S. 279, 309 (1991). These
“rare” errors are those undermining “the constitution of the
trial mechanism”: the presence of a biased judge or the denial
of the right to counsel. Id. Such errors are not redeemable by
retrospective analysis or by retrospective action. Such is not
the case here. Nonetheless, the defendants assert that they
were deprived of substantial rights and the magistrate judge
did not remedy the deprivation. Was the error without effect
on the substantial right of these defendants?

   [7] Unproved Effects. One of the district judges reviewing
the magistrate judge’s procedure reviewed for plain error, put-
ting the burden on defendants to show that the errors affected
their substantial rights. Other of the judges reviewed for
harmlessness, putting the burden on the government to estab-
lish it. We believe that plain error was the correct legal test.
The standard depends on whether the Rule 11 errors were pre-
served. We hold that they were not, so plain error should have
been the standard applied by each district judge.

   Before the March 5 proceedings were terminated the mag-
istrate judge inquired of the four defendants whether they had
committed the elements of the offense. Hannan did not ask
the court to determine the voluntariness of their pleas. The
record shows the magistrate judge seeking to satisfy Hannan’s
15716           UNITED STATES v. ROBLERO-SOLIS
objections. It shows no discontent let alone objection by him
to what she provided.

   On March 6, Hannan did object that the court should indi-
vidually assess the knowing and voluntary character of the
two defendants’ pleas; but when the magistrate judge
responded by interrogating him, he did not say, “That’s not
my point. You have to get the answers from them.” The court
could not have understood from his acquiescence that he was
secretly preserving his objection. It was waived. Plain error is
the standard.

   [8] That standard is set by United States v. Dominguez
Benitez, 542 U.S. 74 (2004). The defendants must show that
their substantial rights have been affected. Therefore, each
defendant “must show a reasonable probability that, but for
the error, he would not have entered the plea.” Id. at 83. None
of these defendants has made such a showing or even
attempted it. Consequently, the judgments of conviction must
be upheld and the judgment of acquittal must be reversed.

   For the foregoing reasons, the judgment in Martinez is
REVERSED. The judgments in Roblero-P, Roblero-S., Ros-
ales, Vasquez and Zarazua are AFFIRMED.
