Whether a certificate of appealability must issue under 28 U.S.C. § 2253 when a state prisoner demonstrates that reasonable jurists could debate whether a federal habeas petition raising substantial constitutional claims should have been resolved differently, notwithstanding circuit court disagreement on the proper application of the Slack standard

were adequate to deserve encouragement to proceed further.” Slack v. McDaniel, 529 U.S. 473, 484 (2000) (quotation marks omitted). In this case, the Sixth Circuit denied Gordon’s petition for a COA in a 2-1 decision, in which one of the panel judges would have granted a COA on two of the habeas claims Gordon raised, as well as the magistrate judge who considered the federal habeas petition before the district court. Respondent is the warden of the Ohio state prison where petitioner is serving an aggregate sentence of ten years imprisonment. App. A, at 1. ! Gordon’s pro se rehearing petition, sent from prison, was considered by the Clerk’s Office of the Sixth Circuit to be two days late. See Doc. 9. The Sixth Circuit gave “careful consideration” to the rehearing petition “referred to this panel” anyway, “for an initial determination on the merits,” which the panel denied in a split decision and then referred “to all of the active members of the court for further proceedings on the suggestion for en banc rehearing.” App. B. This Court’s rules provide that “if a petition for rehearing is timely filed in the lower court ... or if the lower court appropriately entertains an untimely petition for rehearing or sua sponte considers rehearing, the time to file the petition for a writ of certiorari ... runs from the date of the denial of rehearing.” Sup. Ct. R. 13.3. Ninety days from July 10, 2023, is Sunday, October 8, 2023. Thus, absent an extension, the petition is due on October 9, 2023. See Sup. Ct. R. 30.1. In March 2015, Gordon was charged in Ohio state court with two counts of aggravated robbery, two counts of felonious assault, and one count of kidnapping, along with “firearm specifications as to each count.” App. A, at 1. These charges arose from the robbery and shooting of Gordon’s friend, Tevaughn Darling. Jbid. After an edited version of Darling’s videotaped statement to police appeared on social media, Gordon was charged with witness intimidation. [bid. The prosecution moved to join the two cases and to disqualify Gordon’s retained counsel, because Gordon’s chosen counsel in his robbery, assault, and kidnapping case would be a material witness in the intimidation case that arose after he was charged. Jbid. The trial court granted both motions over Gordon’s objection to the disqualification of his counsel of choice. Ibid. A jury subsequently convicted Gordon of the crimes and associated firearm specifications he was originally charged with, but the jury acquitted Gordon of the intimidation charge brought in the second case, the joinder of which resulted in disqualification of his originally retained counsel. Ibid. Thus, while Gordon ultimately was not convicted of intimidating a witness, joining the cases deprived Gordon of the counsel he retained to represent him on the charges over which he was convicted. The trial court imposed an aggregate sentence of ten years of imprisonment. Ibid. On direct appeal, the Ohio Court of Appeals reversed Gordon’s convictions and ordered a retrial, finding that the trial court committed plain error in joining the two cases because joinder prevented him from retaining his counsel of choice, in violation of the Sixth and Fourteenth Amendments. See App. A, at 2. But the Supreme Court of Ohio reversed and remanded for consideration of Gordon’s other claims of error. Ibid. Finding no other error on remand, the Ohio Court of Appeals affirmed Gordon’s conviction and sentence. Ibid. Gordon filed a timely habeas petition in federal court arguing, among other claims, that he was denied counsel of choice by the improper joinder, and that he was provided ineffective assistance of both trial and appellate counsel regarding that claim. App. A, at 2. The magistrate judge recommended denying the petition but granting a certificate of appealability as to Gordon’s denial-of-counsel claim. App. A, at 2-3. Instead, and over Gordon’s objection, the district court denied the petition and declined to grant a C