 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued November 12, 2019              Decided April 10, 2020

                        No. 19-1100

 IN RE: MUSTAFA AHMED AL HAWSAWI AND KHALID SHAIKH
                    MOHAMMAD,
                    PETITIONERS


                 Consolidated with 19-1117


   On Petition for Writ of Mandamus and Prohibition and
              Petition for a Writ of Mandamus
 to the United States Court of Military Commission Review
                and the Military Commission


     Suzanne M. Lachelier, Senior Attorney, Office of Military
Commissions Defense Organization, argued the cause for
petitioner Mustafa Ahmed Al Hawsawi. Edwin A. Perry,
Trial Attorney, argued the cause for petitioner Walid M.
Mubarak Bin 'Atash. With them on the petitions and the joint
reply were Rita Radostitz, Senior Trial Attorney, Walter B.
Ruiz and Sean M. Gleason, Attorneys, and Lt. Col. Derek A.
Poteet, Office of the Chief Defense Counsel.

    Jeffrey M. Smith, Attorney, U.S. Department of Justice,
argued the cause and filed the opposition to the petitions for
writs of mandamus. Sharon Swingle, Attorney, entered an
appearance.
                               2
    Before: HENDERSON and TATEL, Circuit Judges, and
GINSBURG, Senior Circuit Judge.

    Opinion for the Court filed by Circuit Judge HENDERSON.

     KAREN LECRAFT HENDERSON, Circuit Judge:               The
petitioners are being tried before a military commission at
Guantanamo Bay, Cuba, for their alleged roles in the
September 11th terrorist attacks. They seek writs of mandamus
vacating all orders issued by the former presiding military
judge, Marine Corps Colonel Keith Parrella, because of the
appearance of partiality that they claim was created by his
earlier work at the United States Department of Justice (DOJ),
his acquaintance with one of the military commission
prosecutors, the possibility that he might seek a position with
the DOJ in the future and his alleged lack of candor regarding
potential grounds for disqualification. Because it was neither
clear nor indisputable that Parrella was obligated to recuse
himself, we deny the petitions.

                        I. Background

     Khalid Shaikh Mohammad (Mohammad), Walid
Muhammad Salih Mubarak bin ‘Atash (bin ‘Atash) and
Mustafa Ahmed Adam al Hawsawi (Hawsawi) are three of the
five defendants being tried before a twelve-member United
States Military Commission at Guantanamo Bay created
pursuant to the Military Commissions Act of 2009
(Commission), see 10 U.S.C. §948b, for their alleged roles in
the September 11th terrorist attacks (we refer to the petitioners
collectively as the “Guantanamo defendants” unless otherwise
noted). United States Army Colonel James Pohl was initially
detailed to preside on the Commission but, in 2018, Pohl
stepped down and detailed United States Marine Corps Colonel
Keith Parrella (Parrella) to preside in his place. Upon assuming
that position, Parrella provided the Guantanamo defendants
                                3
with a short summary of his career. The summary recited that
in 2014 Parrella served as a counterterrorism prosecutor in the
DOJ’s Counterterrorism Section (CTS) as part of a nine-month
fellowship.

     The defendants sought discovery regarding the fellowship,
but the prosecution declined to provide it. They then moved to
compel discovery, asserting that Parrella “possessed a personal
bias or prejudice concerning a party, has served as a counsel in
the same general case, and/or has expressed an opinion
concerning the guilt or innocence of the Accused.” Bin ‘Atash
Petition at 6. The Commission held a hearing on the motion.
Before the hearing, Parrella distributed a copy of his U.S.
Marine Corps Fitness Report that discussed his DOJ
fellowship. At the hearing, the defendants conducted a voir dire
of Parrella.

     The voir dire focused on Parrella’s work at the CTS and
his relationship with members of the prosecution team. 1
Parrella indicated that he was co-detailed to several terrorism-
related cases while with the CTS but he explained that he did
not work on any matter involving the Commissions, the
September 11th attacks or al-Qaeda. In response to
questioning, Parrella stated that he had some limited
interaction with the FBI and CIA, namely conducting
document review at warehouses or facilities controlled by



    1
        Approximately forty lawyers worked in the CTS at the time
of Parrella’s fellowship. Many of the prosecutors who appear before
the Commission were, and are, assigned from the DOJ’s National
Security Division (NSD), of which the CTS is a part. While assigned
to the Commission, the prosecutors conduct their work from the
Office of the Chief Prosecutor of the Office of Military
Commissions.
                                  4
those agencies. He declined to provide further details, citing
lack of memory and his duty of confidentiality.

     Parrella also indicated that he was familiar with a member
of the defendants’ prosecution team, Jeffrey Groharing.
Parrella and Groharing first met when they were both stationed
in San Diego during the late 90s and early 2000s. Parrella
indicated that the two had little interaction at that time and were
best described as “acquaintance[s].” 9/11: Khalid Shaikh
Mohammad et al. (2) Military Commission Transcript 20505
(Sept. 10, 2018) (unofficial). Parrella and Groharing interacted
again in 2007 and 2008, when they twice competed together on
a four-man team in an endurance race called the “Wilderness
Challenge.” Parrella stated that he organized the team and
selected Groharing as a member based on his reputed athletic
ability. Other members of the team interviewed by the
Guantanamo defendants explained that Groharing was
included on the team on the recommendation of one of the
other members. The team did not train together and met only
for the two races. 2 Finally, Parrella indicated that he saw
Groharing “a couple of times” while they were both at the DOJ
(Parrella as a CTS fellow, Groharing as a Commission
prosecutor) and at a Marine Corps Ball Ceremony.
Commission Tr. at 20509.



     2
        The Guantanamo defendants suggest that Parrella
misrepresented the extent of his interactions with his “Wilderness
Challenge” teammates. At best, the Guantanamo defendants’
suggestion is accurate only in a technical sense. Parrella explained
that members of the team met up only for the race, but other team
members explained that they did in fact meet the day before the race
to walk the course. They stated that members of the team who were
stationed together trained together but it is undisputed that Parrella
and Groharing were not and did not.
                               5
     The Guantanamo defendants moved to recuse Parrella,
which motion he denied. A month later Hawsawi again sought
Parrella’s recusal. He relied on the same grounds as the original
motion but also alleged that Parrella was evasive in his voir
dire responses. Parrella also denied that motion. Hawsawi then
petitioned for a writ of mandamus before the Court of Military
Commission Review (CMCR) 3 and Mohammad petitioned
separately. See Hawsawi v. United States, 389 F. Supp. 3d
1001, 1003 (CMCR 2019). Bin ‘Atash, after conducting his
own investigation of Parrella’s background, moved to
disqualify and transfer Parrella before Douglas K. Watkins,
Chief Judge of the Military Commissions. Chief Judge
Watkins did not respond to that motion other than to
acknowledge receipt. Parrella denied bin ‘Atash’s motion as
procedurally improper and without merit. Shortly thereafter,
Parrella’s detail as a military judge ended for an unrelated,
routine reason (the beginning of a new assignment). Hawsawi
then petitioned our court for mandamus relief. The CMCR
subsequently denied Hawsawi’s and Mohammad’s mandamus
petitions. See Hawsawi, 389 F. Supp. 3d at 1014. Mohammad
then joined Hawsawi’s petition. Bin ‘Atash separately filed a
mandamus petition with our court and the petitions were
consolidated. See Order, In re Hawsawi (D.C. Cir. May 31,
2019). We now consider the consolidated petitions.

                          II. Analysis

    This court has exclusive jurisdiction of appeals from both
the military commissions and the CMCR. 10 U.S.C. § 950g.
We may issue all writs necessary and appropriate, including
mandamus, in aid of our jurisdiction. 28 U.S.C. § 1651; In re
Al-Nashiri, 921 F.3d 224, 233 (D.C. Cir. 2019) (Al-Nashiri III).


    3
        The CMCR hears both interlocutory and final appeals from
the military commissions. See 10 U.S.C. §§ 950d, 950f.
                                 6
We have previously held that “mandamus provides ‘an
appropriate vehicle for seeking recusal of a judicial officer
during the pendency of a case.’” Al-Nashiri III, 921 F.3d at 233
(quoting In re Mohammad, 866 F.3d 473, 475 (D.C. Cir.
2017)). That power extends to vacating the issued orders of a
judge who should have recused. Id. at 240. Still, the “traditional
prerequisites for mandamus relief” must be satisfied. Id. at 233
(quoting In re Al-Nashiri, 791 F.3d 71, 78 (D.C. Cir. 2015)).
“For a court to grant a writ of mandamus, three conditions must
be met: the petitioner must demonstrate that his right to
issuance of the writ is clear and indisputable, the party seeking
issuance of the writ must have no other adequate means to
attain the relief he desires, and the issuing court, in the exercise
of its discretion, must be satisfied that the writ is appropriate
under the circumstances.” Id. at 233 (internal quotation marks
and brackets omitted) (quoting Cheney v. United States Dist.
Ct., 542 U.S. 367, 380 (2004)). The Guantanamo defendants
claim that they meet all three prerequisites. The prosecution
disputes only the first.

     Before we address the merits of the petitions, however, we
clarify the standard of review to be applied to a petition for
mandamus to order a judge to recuse himself. The prosecution
relies on our decision in United States v. Cordova, 806 F.3d
1085, 1092 (D.C. Cir. 2015), where, on direct review, we
reviewed the denial of a recusal motion for abuse of discretion,
and maintains that we should assess whether the defendants
have established “that it is clear and indisputable that Judge
Parrella committed an abuse of discretion when he declined to
recuse.” Resp’t Br. at 16. We read this request as one to
combine our “clear and indisputable” standard with the “abuse
of discretion” standard in the manner adopted by several sister
circuits. See, e.g., In re Bulger, 710 F.3d 42, 45–46 (1st Cir.
2013).
                                7
     To the extent the prosecution urges us to adopt this
“combined” test, we reject its invitation. Our cases have
consistently required a mandamus petitioner to demonstrate a
“clear and indisputable” right to relief, without more. See, e.g.,
Al-Nashiri III, 921 F.3d at 233 (petitioner must show “clear and
indisputable” right to relief); In re Mohammed, 866 F.3d 473
(D.C. Cir. 2017) (per curiam) (same); In re Khadr, 823 F.3d
92, 100 (D.C. Cir. 2016) (same); In re Brooks, 383 F.3d 1036,
1041 (D.C. Cir. 2004) (same). Although we have occasionally
referenced the “abuse of discretion” standard in those
decisions, see, e.g., In re Brooks, 383 F.3d at 1038 (“We now
deny the petition to recuse Judge Lamberth from the pending
contempt proceedings because . . . we have no reason to
conclude he abused his discretion by refusing to recuse
himself.”); In re Al Baluchi, No. 19-1146, 2020 WL 1222825,
at *5 (D.C. Cir. Mar. 13, 2020) (citing Cheney’s “clear and
indisputable” standard alone, before later explaining petitioner
must show “that it is ‘clear and indisputable’ that the
Commission abused its discretion”), those decisions make
clear that our court has not adopted a “combined” or “doubly
deferential” test, In re Bulger, 710 F.3d at 45–46.

     In any event, consistent with our precedent and that of the
Fifth, Tenth and Eleventh Circuits, we assess whether to grant
the Guantanamo defendants’ requested relief using the specific
standard for mandamus relief alone. See In re Moody, 755 F.3d
891, 898 (11th Cir. 2014); Nichols v. Alley, 71 F.3d 347, 350
(10th Cir. 1995); In re Dresser Industries, Inc., 972 F.2d 540,
542–43 (5th Cir. 1992). At the same time, we keep in mind that
“[m]andamus is a drastic and extraordinary remedy reserved
for really extraordinary causes.” In re Khadr, 823 F.3d at 97
(internal quotation marks omitted) (quoting Cheney, 542 U.S.
at 380).
                                 8
      Several sources set out Parrella’s recusal obligations. See
28 U.S.C. § 455; Code of Conduct for United States Judges;
America Bar Association Model Code of Judicial Conduct;
Rules for Courts-Martial; Rules for Military Commissions
(R.M.C.). In our most recent decision disqualifying a
Commission judge, we relied on all of these sources to assess
whether the judge should have recused himself and held that
“[t]hese assembled sources of rules governing judicial conduct
. . . all speak with one clear voice when it comes to judicial
recusal: judges ‘shall disqualify’ themselves in any
‘proceeding in which their impartiality might reasonably be
questioned.’” Al-Nashiri III, 921 F.3d at 234 (brackets omitted)
(quoting 28 U.S.C. § 455(a); Code of Conduct for United States
Judges, Canon 3(C)(1); American Bar Association, Model
Code of Judicial Conduct, Rule 2.11; Rule for Courts-Martial
902(a)).4 In other words, a judge must recuse himself if there
“is ‘a showing of an appearance of bias . . . sufficient to permit
the average citizen reasonably to question a judge’s
impartiality.’” Al-Nashiri III, 921 F.3d at 234 (quoting United
States v. Heldt, 668 F.2d 1238, 1271 (D.C. Cir. 1981)). A judge
should be careful, however, to avoid “provid[ing] litigants with
a veto against unwanted judges.” In re Boston’s Children First,
244 F.3d 164, 167 (1st Cir. 2001); see also United States v.
Microsoft Corp., 253 F.3d 34, 108 (D.C. Cir. 2001)
(“Disqualification is never taken lightly. In the wrong hands, a
disqualification motion is a procedural weapon to harass
opponents and delay proceedings.”); In re Kaminski, 960 F.2d
1062, 1065 n.3 (D.C. Cir. 1992) (“A judge should not recuse
himself based upon conclusory, unsupported or tenuous




    4
        We note that the Rules for Military Commissions and the
Rules for Courts-Martial are discrete rules, as Al-Nashiri III makes
clear. See Al-Nashiri III, 921 F.3d at 234.
                                   9
allegations.”) (citing Giles v. Garwood, 853 F.2d 876, 878
(11th Cir. 1988)).

    Al-Nashiri III, our most recent precedent involving a
Guantanamo Bay detainee, discussed only the standards
contained in 28 U.S.C. § 455(a) (“Any . . . judge . . . of the
United States shall disqualify himself in any proceeding in
which his impartiality might reasonably be questioned.”) and
R.M.C. 902(a) (“[A] military judge shall disqualify himself or
herself in any proceeding in which that military judge’s
impartiality might reasonably be questioned.”). But both 28
U.S.C. § 455 5 and R.M.C. 902 6 also specifically address


    5
         As relevant here, 28 U.S.C. § 455 provides:
            (a) Any justice, judge, or magistrate judge of the
        United States shall disqualify himself in any proceeding
        in which his impartiality might reasonably be
        questioned.
             (b) He shall also disqualify himself in the
        following circumstances:
                   (1) Where he has a personal bias or
              prejudice concerning a party, or personal
              knowledge of disputed evidentiary facts
              concerning the proceeding;
             ...
                   (3)      Where he has served in
              governmental employment and in such
              capacity participated as counsel, adviser
              or material witness concerning the
              proceeding or expressed an opinion
              concerning the merits of the particular
              case in controversy[.]
    6
         As relevant here, R.M.C. 902 provides:
                                 10
recusal based on earlier government service. 28 U.S.C. §
455(b)(3) requires a judge to “disqualify himself . . . [w]here
he has served in governmental employment and in such
capacity participated as counsel, adviser or material witness
concerning the proceeding or expressed an opinion concerning
the merits of the particular case in controversy” and R.M.C.
902(b)(2) requires a military judge to disqualify himself if he
“acted as counsel, legal officer, staff judge advocate, or
convening authority as to any offense charged or in the same
case generally.” The United States Supreme Court addressed
the relationship between sections 455(a) and (b) in Liteky v.
United States, 510 U.S. 540 (1994). There, the Court reviewed
a motion to disqualify the presiding judge in a criminal trial
based on statements and decisions the judge made during an
earlier trial. The issue before the Court was whether section
455 incorporated the historic rule that a judge need only recuse
himself when alleged bias flowed from “extrajudicial sources.”

           (a) In general. Except as provided in section (e) of
      this rule, a military judge shall disqualify himself or
      herself in any proceeding in which that military judge’s
      impartiality might reasonably be questioned.
           (b) Specific grounds. A military judge shall also
      disqualify himself or herself in the following
      circumstances:
                 (1) Where the military judge has a
            personal bias or prejudice concerning a
            party or personal knowledge of disputed
            evidentiary    facts   concerning   the
            proceeding.
                 (2) Where the military judge has
            acted as counsel, legal officer, staff judge
            advocate, or convening authority as to any
            offense charged or in the same case
            generally.
                               11
The Court declared that section 455(b)(1), by providing that a
judge shall “disqualify himself . . . [w]here he has a personal
bias or prejudice concerning a party,” incorporates the source
of the alleged bias. Id. at 550. It then went on to hold that in
assessing whether a judge’s “impartiality could reasonably be
questioned” under section 455(a) a court must also consider the
source of the alleged “appearance of partiality.” Id. at 553. It
explained its reasoning thus:

       Declining to find in the language of § 455(a) a
       limitation which (petitioners acknowledge) is
       contained in the language of § 455(b)(1) would
       cause the statute, in a significant sense, to
       contradict itself. As we have described, § 455(a)
       expands the protection of § 455(b), but
       duplicates some of its protection as well—not
       only with regard to bias and prejudice but also
       with regard to interest and relationship. Within
       the area of overlap, it is unreasonable to
       interpret § 455(a) (unless the language requires
       it) as implicitly eliminating a limitation
       explicitly set forth in § 455(b).

Id. at 552–53. The Court elaborated that “[i]t is correct that
subsection (a) has a broader reach than subsection (b) . . . .
[h]owever, when one of those aspects addressed in (b) is at
issue, it is poor statutory construction to interpret (a) as
nullifying the limitations (b) provides, except to the extent the
text requires.” Id. at 553 n.2 (internal quotation marks omitted).

     A judge on our court has construed Liteky in the context of
section 455(b)(3), which requires recusal based on certain roles
performed in earlier “government employment.” In Baker &
Hostetler LLP v. U.S. Dep’t of Commerce, then–Judge
Kavanaugh addressed a motion for his recusal based on his
                                12
earlier Executive Branch employment. 471 F.3d 1355 (D.C.
Cir. 2006). He explained that in section 455(b)(3), “Congress
clearly and specifically addressed the effect of prior
government service on a judge’s recusal obligations” and “[i]n
determining whether recusal is appropriate or inappropriate
based on prior government employment, judges must respect
the line drawn by Congress.” Id. at 1357–58. Consequently,
because his earlier Executive Branch work did not fall within
section 455(b)(3)’s prohibition, Judge Kavanaugh declined to
recuse himself under both section 455(a) and section 455(b)(3).
Id. at 1358.

     The Guantanamo defendants maintain that we should
decide whether one could reasonably believe that Parrella’s
fellowship at the CTS created a question regarding his
partiality without relying on section 455(b)(3) or R.M.C.
902(b)(2). In their view, “[i]n the actual holding [in Liteky], the
Supreme Court held that 28 U.S.C. § 455(a) expands the
protection of § 455(b), but duplicates some of its protection as
well—not only with regard to bias and prejudice but also with
regard to interest and relationship.” Pet’r Reply Br. at 3–4
(quoting Liteky, 510 U.S. at 552). They read Liteky as
“highlight[ing] that the appearance of bias is a broader basis
for recusal than the specific grounds enumerated in Section
455(b).” Id. at 4. They also attempt to harness Judge
Kavanaugh’s opinion in Baker & Hostetler to their argument,
pointing to his explanation that “Section 455(a)’s general
‘catch-all’ provision . . . covers situations not addressed by
455(b) that nonetheless might be appropriate for recusal.” Id.
at 5 (quoting Baker & Hostetler, 471 F.3d at 1357). Finally, the
Guantanamo defendants point out that both section 455(b) and
R.M.C. 902(b) begin with the language “shall also disqualify”,
maintaining that “also” “dispels [the prosecution’s] argument
that Rule 902(b) trumps any claim about the appearance of
bias.” Id. at 4.
                               13
     We cannot adopt the defendants’ reading of precedent or
of the pertinent disqualification provisions. In Liteky, the
Supreme Court held that section 455(a) “expands” the
protection of section 455(b) but it also clarified that it would
be “poor statutory construction to interpret (a) as nullifying the
limitations (b) provides.” Liteky, 510 U.S. at 553 n.2. The
Court was clear that, if an issue is within the scope of section
455(b), section 455(a) should not be read to require
disqualification if section 455(b) does not. Judge Kavanaugh
was also clear that section 455(a) should not be used to resolve
a question that 455(b) addresses. The statement quoted by the
Guantanamo defendants itself makes that point. See Baker &
Hostetler, 471 F.3d at 1357 (“[S]ection [455(a)] covers
situations not addressed by 455(b).” (emphasis added)).
Moreover, however persuasive the Guantanamo defendants’
reading of the statute may be in theory, it was available to the
Supreme Court and the Court did not adopt it. In sum, except
in “rare and extraordinary circumstances,” Baker & Hostetler,
471 F.3d at 1358, a Commission judge need not recuse himself
because of his earlier government service unless he either (1)
“acted as counsel, legal officer, staff judge advocate, or
convening authority as to any offense charged or in the same
case generally,” R.M.C. § 902(b)(2), or (2) “participated as
counsel, adviser or material witness concerning the proceeding
or expressed an opinion concerning the merits of the particular
case in controversy,” 28 U.S.C. § 455(b)(3).

    The Guantanamo defendants first argue that Parrella
should have recused himself because of his previous work at
the CTS. Reviewed under the authority discussed above, we
think it is neither clear nor indisputable that Parrella’s work at
the CTS, including any interactions he had with the CIA and
FBI, obliged him to recuse himself. He testified that none of
the work he performed at the CTS bore any relation to the
Commission, the September 11th attacks or al-Qaeda. The
                               14
Guantanamo defendants did not rebut that testimony. We see
nothing “rare and extraordinary” in Parrella’s earlier
government service. Accordingly, we decline to find that
Parrella should have disqualified himself because of his work
as a CTS fellow.

     We turn to the other grounds for recusal pressed by the
Guantanamo defendants. They argue that Parrella’s “two-
decade-long friendship” and “close relationship” with
Groharing, his alleged lack of forthrightness at voir dire and
the fact that he did not rule out post-retirement DOJ
employment created an appearance of partiality. Because
neither party suggests that any ethical rule or statutory
provision expressly addresses these grounds for
disqualification, we evaluate them under the general
appearance of partiality standard set forth in 28 U.S.C. § 455(a)
and R.M.C. 902(a).

     A judge’s past social relationship with a participant in a
proceeding does not generally require recusal in either the
civilian or the military justice systems. See United States v.
Sullivan, 74 M.J. 448, 455 (C.A.A.F. 2015) (military judge’s
disqualification was not required where “the number and type
of contacts that the military judge had with the participants in
the court-martial appear to simply be a natural consequence of
the military judge’s length of service”); Henderson v. Dep’t of
Pub. Safety & Corr., 901 F.2d 1288, 1295–96 (5th Cir. 1990)
(“[E]ven the most superficial research would have put
[counsel] on notice” that allegation that judge had “known the
opposing counsel since he was a kid and . . . was friends [with]
opposing counsel and opposing counsel’s father” was not
ground for recusal). That includes a past relationship with a
party’s counsel. See Henderson, 901 F.2d at 1295–96; United
States v. Murphy, 768 F.2d 1518, 1537 (7th Cir. 1985) (“In
today’s legal culture friendships among judges and lawyers are
                               15
common. They are more than common; they are desirable . . . .
Many courts therefore have held that a judge need not
disqualify himself just because a friend—even a close friend—
appears as a lawyer.” (string cite omitted)); Philip Morris USA
v. United States FDA, 156 F. Supp. 3d 36, 53 (D.D.C. 2016)
(same). Granted, such a relationship can sometimes be a
ground for disqualification. See, e.g., Murphy, 768 F.2d at 1538
(“These cases also suggest . . . that when the association
exceeds what might reasonably be expected in light of the
association activities of an ordinary judge, the unusual aspects
of a social relation may give rise to a reasonable question about
the judge’s impartiality.”(citation omitted)). The question is
whether Parrella’s relationship with Groharing was so close or
unusual as to be problematic.

     The evidence before us indicates that it was not
problematic. Contrary to the Guantanamo defendants’
characterization of Parrella’s relationship with Groharing, by
all accounts it was cordial but not intimate. Their participation
together in the “Wilderness Challenge” races may raise a
question on its face but Parrella adequately addressed any
concern by explaining that the two did not interact beyond the
races themselves during that time, testimony that was
confirmed by other team members. The defendants have not
cited any case in which a similar relationship has been found
problematic and we know of none. To the contrary, other courts
have concluded that a relationship between a judge and counsel
closer than what is at issue here did not require recusal. See,
e.g., Henderson, 901 F.2d at 1295–96 (no ground for recusal
when judge had known counsel appearing before him “since
[counsel] was a kid”).

   The Guantanamo defendants argue that required ex parte
communications between the prosecution and the presiding
Commission judge distinguishes their petitions from those
                               16
decisions that have declined to require disqualification based
on a social relationship between a judge and counsel appearing
before him. We disagree. We do not see how the necessary use
of ex parte communications in the Commission proceedings
substantially increased the appearance of partiality created by
Parrella’s past relationship with Groharing.

     Ultimately, someone aware of all the facts would not be
reasonably likely to believe that Parrella was partial to
Groharing on account of their limited social relationship. This
is particularly true after the full voir dire Parrella allowed and
his assurance that his relationship with Groharing would not
affect his decisions. See Sullivan, 74 M.J. at 454 (military
judge’s recusal was not required in part because he disclosed
potentially problematic relationships, subjected himself to voir
dire and indicated his associations would not influence his
decisions); United States v. Wright, 52 M.J. 136, 141 (C.A.A.F.
1999) (“[D]espite an objective standard, the judge’s statements
concerning his intentions and the matters upon which he will
rely are not irrelevant to the inquiry.”). Accordingly, we
believe that Parrella’s relationship with Groharing did not
require his recusal.

     Next, we assess the Guantanamo defendants’ claim that
Parrella’s behavior during voir dire created an appearance of
partiality. They repeatedly suggest that Parrella was less than
forthcoming during the hearing, describing him as “terse and
obstructionist” and stating that “Judge Parrella refused to
answer any questions about the appearance of bias or questions
about whether his prosecutorial work with the CTS and his
relationship with the prosecution team could possibly have an
impact on his consideration in the case.” Bin ‘Atash Petition at
25–27. They contend that his alleged lack of candor is a ground
to find that Parrella exhibited an appearance of partiality.
                               17
     A judge’s lack of candor about potential grounds for
recusal can of course produce an appearance of partiality. See
Al-Nashiri III, 921 F.3d at 237 (“Given this lack of candor, a
reasonable observer might wonder whether the judge had done
something worth concealing.”). But the Guantanamo
defendants mischaracterize Parrella’s responses and conduct at
the recusal hearing. Parrella submitted himself to several hours
of probing questions by the Guantanamo defendants’ counsel
about various aspects of his professional experience and
personal relationships, including his time at the CTS and his
relationship with Groharing. These questions were expressly
intended to suss out any actual or apparent partiality and
Parrella appears to have answered them fully and forthrightly.
The only instances that Parrella could plausibly be said to have
withheld information from the Guantanamo defendants were
his failure to affirmatively disclose his relationship with
Groharing before the hearing and his refusal to answer detailed
questions about his past interactions with the CIA and FBI. In
both cases, however, he provided explanations sufficient to
mitigate any lack of candor that might otherwise have
attached—as to the former, Parrella explained that he had not
mentioned Groharing earlier because he did not believe the
relationship was problematic, that he was certain it would come
up at the hearing and that he would have brought it up himself
had it not. As to the latter, he cited lack of memory and his
continuing duty of confidentiality. Given that Parrella’s
relationship with Groharing was unproblematic, there is no
indication that he was attempting to conceal that relationship.
And because his explanation for failing to answer detailed
questions about his interactions with the CIA and the FBI is
plausible, we do not believe that Parrella’s responses, or failure
to respond, to the Guantanamo defendants’ questioning created
the appearance of partiality.
                              18
     The Guantanamo defendants also briefly suggest that
Parrella should have recused himself because he did not rule
out future DOJ employment. We cannot agree. Parrella
affirmatively stated that he had no plans to seek employment
with the DOJ, or anywhere else in the federal government for
that matter, after his retirement. That fact makes this case
entirely unlike the situation presented in Al-Nashiri III, where
the presiding judge—while presiding—engaged in a covert,
two-year negotiation regarding a DOJ position and accepted
the position immediately after issuing a high-profile ruling in
that case. Moreover, requiring a judge to recuse himself simply
because he cannot rule out the possibility of future employment
with a party appearing before him has no basis in precedent and
could prove unworkable.

     Reviewing all of the grounds for recusal proffered by the
Guantanamo defendants together—Parrella’s CTS fellowship,
his relationship with Groharing, the possibility of future DOJ
employment and his voir dire responses—we conclude that it
is neither clear nor indisputable that Colonel Parrella should
have recused himself. The circumstances of Parrella’s career
and relationships do not constitute reasonable bases for the
extraordinary remedy of mandamus.

    For the foregoing reasons, we deny the petitions.

                                                    So ordered.
