OPINION OF THE COURT
Clayton Lilly appeals to us from the District Court’s denial of his petition for habeas corpus. He argues that the District Court should have granted him an evidentiary hearing to develop his claim that his counsel was ineffective in failing to advise him adequately about waiving his right to a jury trial. We disagree, and thus affirm the petition’s denial.
I.
In 2001, law enforcement officials began investigating Lilly after they received information from a confidential informant that he was selling crack cocaine over the counter of the clothing store he owned and operated. After police observed Lilly engage in a variety of drug transactions, they applied for a warrant to search him, his store, and his car. To avoid destruction of evidence, police detained Lilly while waiting for the searсh warrant. Upon executing the warrant, police found crack cocaine in Lilly’s store as well as in his car and on his person. Lilly then stated, “It’s hard selling these clothes. The guys aren’t buying these clothes. I have to support myself.” Lilly was arrested. Police subsequently secured a search warrant for Lilly’s home, where they discovered large amounts of crack cocaine. The combined searches yielded 162.54 grams of crack cocaine.
A grand jury indicted Lilly for possession with intent to distribute in excess of 50 grams of a substance containing cocaine base, in violation of 21 U.S.C. §§ 841(a)(1) and 841(b)(l)(A)(iii). Prior to trial, Lilly’s attorney, William E. Stockey, Esq., filed a motion to suppress the evidence police had seized. Because the evidence in support of the motiоn to suppress was almost identical to the evidence that would be presented at trial, the parties allegedly agreed to proceed with a non-jury trial where the District Court would hear the evidence on the suppression motion and the trial together. However, Lilly and his attorney did not sign a written waiver of his jury-trial right pursuant to Federal Rule of Criminal Procedure 23(a) until some six wеeks after the non-jury trial was complet
In November 2001, the District Court conducted a one-day joint pre-trial hearing and non-jury trial where it heard all of the evidence. At the beginning of the proceedings, the Court confirmed with the parties their intent to have a non-jury trial:
The Court: I think the record should show that both the government and the defendant have requested a non-jury trial; is that correct?
[Government] That’s correct for the government, Your Honor.
Mr. Stockey: Correct for the defendant, Judge.
Mr. Lilly was present for this interchange, but he did not speak up, nor did the Court ask him directly to confirm his desire to waive a jury trial.
The Court then heard evidence on the suppression motion and the case simultaneously. The Government based its case on the cocaine that police had seized in its searches of Lilly’s person, business, car, and home. Lilly conceded that the searches had yielded a large quantity of cocaine, but argued that the search warrants were unsupported by probable cause because the police officers and the confidential informant were not credible. He further argued that the Government had not established beyond a reasonable doubt that Lilly was guilty because, among other things, it had not called the confidential informant to testify, nor had it established that Lilly had the lavish lifestyle one would expect of a drug dealer.
After hearing all of the evidence, the Court found the police officers to be credible and denied Lilly’s motion to suppress. In late December 2001, the Court issued its findings of fact and found Lilly guilty. At sentencing, the Pre-Sentence Investigation Report classified Lilly as а career offender under the United States Sentencing Guidelines, giving him a Guidelines range of 360 months to life imprisonment. Lilly filed a motion for downward departure on the basis that the career-offender designation overrepresented his criminal history. The Court granted the motion and sentenced Lilly to a 188-month term of imprisonment.
Lilly appealed his conviction. Stockey, his trial counsеl, initially represented Lilly on appeal, but then withdrew because Lilly and his family could no longer afford his representation. Our Court appointed new appellate counsel. We affirmed Lilly’s conviction in March 2003.
In March 2004, Lilly filed a pro se habe-as petition under 28 U.S.C. § 2255. In it, Lilly alleged, inter alia, that Stockey had been ineffective in failing to advise him of his right to a jury trial and in failing to obtain from him a written, signed waiver of that right. Lilly further alleged that Stockey had “tricked” him intо signing the written waiver six weeks after trial.
One month after filing the initial pro se petition, Lilly filed a supplemental pro se habeas petition alleging that he was denied his constitutional right to a jury trial when his counsel waived it without his consent. 1 He further asserted that the District Court would have learned all of this had it conducted a colloquy with him directly before accepting his waiver. The Government filed a single response to both petitions contending that Lilly had been informed of his right to а jury trial and had knowingly and voluntarily waived it.
3. I am aware that Mr. Lilly has filed a Motion to Vacate under 28 U.S.C. § 2255.... I am also aware that Mr. Lilly claims that I did not advise him of his right to a jury trial in the present case.
4. I did inform Mr. Lilly that he had a right to trial by jury. On September 28, 2001 and at subsequent meetings I also advised him to waive that right and proceed with a bench trial.
5. Mr. Lilly took my advice. He knowingly and willingly waived his right to jury trial. In fact, he even signed a written wаiver of his right to jury trial that I filed with this court before a verdict was entered in this case.
The District Court concluded that an evidentiary hearing was not necessary and denied Lilly’s § 2255 petition in its entirety. With regard to Lilly’s claims about his waiver of a jury trial, the District Court understood him to be making two distinct arguments that his counsel was ineffective (1) in failing to advise him that he had a right to a jury trial, and (2) in failing to have him sign a written Rule 23(a) waiver of a jury trial before trial began. The Court found that the record belied Lilly’s assertion that he was never advised of his right to a jury trial. Specifically, it reasoned that Lilly’s signed waiver post-trial, his trial counsel’s affidavit saying that Lilly had knowingly and willfully waived a jury trial, and the District Court’s pretrial oral confirmation of Lilly’s waiver “demón-stratela] indisputably that [Lilly] was well-aware of his right to a jury trial.”
United States v. Lilly,
With regard to Lilly’s claim about the timing of the written waiver, the Court held that Rule 23(a) does not require that a written jury-trial waiver be filed at any particular time. Thus filing the waiver after trial but before verdict was appropriate. Even assuming that the late waiver showed incompetence by Lilly’s attorney, the Court found no prejudice because it had orally confirmed the waiver with Lilly’s counsel prior to trial in Lilly’s presence.
Finally, the Court noted that it was under no duty to conduct an on-the-record colloquy with Lilly prior to accepting his waiver of .the jury-trial right.
See United States v. Anderson,
Lilly filed a timely notice of appeal and a request for a certificate of appealability with our Court. In his counseled application for a certificate of appealability, he renewed his ineffective assistance and due process claims. We granted a certificate of appealability on the ineffective assistance claim, reasoning that jurists could disagree with the District Court’s holding that Lilly’s counsel was ineffective if he failed to advise Lilly properly of his right to a jury trial and could debate whether the Court should have conducted an evi-dentiary hearing before denying the claim. We declined to issue a certificate of ap-pealability on the due process claim because it was procedurally defaulted, as it was not raised on direct appeal.
II.
The District Court had jurisdiction over Lilly’s § 2255 petition pursuant to 28 U.S.C. § 1331. We have jurisdiction under 28 U.S.C. §§ 1291 and 2253(a). “In a federal habeas corpus proceeding, we exercise plenary review of the district court’s legal conclusions and apply a clearly erroneous standard to the court’s factual findings.”
Lambert v. Blackwell,
III.
Lilly’s sole contention on appeal is that the District Court abused its discretion in not granting an evidentiary hearing on his claim that counsel was ineffective for failing to advise him properly of his right to a jury trial.
3
While the District Court has discretion to conduct an eviden-tiary hearing on a § 2255 claim, exercise of that discretion has been constrained by our case law.
See id.
“The District Court is required to hold an evidentiary hearing ‘unless the motion and files and records of the case show conclusively that the movant is not entitled to relief.’ ”
Id.
(quoting
Gov’t of Virgin Islands v. Forte,
With this in mind, the District Court’s decision not to hold an evidentiary hearing will be an abuse of discretion unless it can be conclusively shown that Lilly cannot make out a claim for ineffective assistance of counsel. It is well-established that the standard for judging ineffective assistance of counsel comes from
Strickland v. Washington,
Lilly asserts that his counsel was ineffective in not explaining to him what waiving a jury trial meant, such that his waiver was “not ‘done with sufficient awareness of the relevant circumstances and likely consequencеs.’ ” Appellant’s Br. 22 (quoting
Brady v. United States,
Our Court has “endorsed the practical suggestion in
Strickland
[that we may] consider the prejudice prong before examining the performance of counsel prong ‘because this course of action is less burdensome to defense counsel.’ ”
Booth,
Lilly argues that the relevant prejudice inquiry is whether he would have opted for a jury trial over a bench trial had his counsel adequately informed him of this constitutional right. Hе grounds his argument on
Hill v. Lockhart,
In determining whether prejudice exists we must assume, absent some allegation to the contrary, “that the judge or jury acted according to law.”
Id.
Moreover, “[t]he assessment of prejudice should proceed on the assumption that the deci-sionmaker is reasonably, conscientiously, and impartially applying the standards that govern the decision. It should not depend on the idiosyncracies of the particular decisionmaker, such as unusual propensities toward harshness or leniency.”
Id.
at 695,
In so holding, we are mindful of the limits of the certifícate of appealability in this case. We are not deciding whether Lilly’s waiver of his right to a jury trial was knowing and voluntary as a matter of due process because that claim was procedurally defaulted when it was not raised on direct appeal. We are merеly considering whether Lilly was entitled to an evidentia-ry hearing on his claim that counsel was ineffective in advising him to waive his right to a jury trial. Because Lilly has failed to establish that this advice prejudiced him in a way that “underminefs] confidence in the outcome,”
Strickland,
IV.
As a final matter, we observe for future cases that much of the doubt in this case could have been avoided had the District Court conducted a thorough, on-the-record colloquy with Lilly directly before accepting his attorney’s statement that Lilly wished to waive his right to a jury trial. While no such colloquy is required under Rule 23(a) or constitutional law,
see United States v. Anderson,
Some form of waiver colloquy has been endorsed by the Courts of Appeals for the First, Second, Fourth, Sixth, Seventh, Ninth, Tenth, and D.C. Circuits, as well as by our own.
See United States v. Leja,
The District Court is, of course, free to fashion the colloquy in the way it sees fit.
See Anderson,
At a minimum, a defendant should be informed that a jury is composed of 12 members of thе community, he may participate in the selection of jurors, the verdict of the jury must be unanimous, and that a judge alone will decide guilt or innocence should he waive his jury trial right.
* * *
In this context, we affirm the District Court’s dismissal of Lilly’s § 2255 petition without an evidentiary hearing.
Notes
. Lilly subsequently made two further supplemental filings in his § 2255 action, but these raised issues not relevant to this appeal.
. AEDPA amended § 2255 to "bar[] second or successive habeas petitions absent exceptional circumstances and certification by the appropriate court of appeals.... To avoid making successive claims, petitioners must marshal in one § 2255 writ all the arguments they have to collaterally attack their convictions.”
United States v. Miller,
. Lilly does not appear to renew on appeal his claim that his counsel was ineffective for failing to file the signed waiver of a jury trial until six weeks after the bench trial (though before the verdict was rendered by the District Judge).
