449 U.S. 368 (1981)
Respondent served as lead counsel for the plaintiffs in four product-liability suits against petitioner Firestone Tire & Rubber Co. and other manufacturers of multipiece truck tire rims.1
The complaints alleged negligent, willful, or intentional failures to correct or to warn of the supposed defects in the rims and sought both compensatory and exemplary damages.2
Petitioner was insured by Home Insurance Co. under a contract with a deductible amount, and Home was an occasional client of respondent's law firm.3 In May 1979, petitioner filed a motion to disqualify respondent, contending that his representation of Home created a conflict because it would incentivize structuring the claims to enable the insurer to avoid liability, thereby increasing petitioner's potential exposure.4 Home had advised petitioner that its policy would not cover awards of compensatory damages for willful or intentional acts or any exemplary or punitive damages.5
The District Court issued a pretrial order requiring respondent to terminate his representation unless both the plaintiffs and Home consented.6 Respondent submitted an affidavit confirming that he had informed the plaintiffs and Home of the potential conflict and that neither objected, supported by affidavits from the plaintiffs and a Home representative, allowing him to continue representing the plaintiffs.7
Petitioner appealed the District Court's decision under 28 U.S.C. § 1291.8 The United States Court of Appeals for the Eighth Circuit, sitting en banc, affirmed the order permitting continued representation but overruled its prior decisions on immediate appealability of such orders, reaching the merits only in fairness to the appellant while holding that future review must await final judgment on the merits.9 The Supreme Court granted certiorari to resolve a conflict among the Circuits regarding the appealability of orders denying disqualification motions.10
Whether a party may take an appeal, pursuant to 28 U.S.C. § 1291, from a district court order denying a motion to disqualify counsel for the opposing party in a civil case?11
Under 28 U.S.C. § 1291, courts of appeals have jurisdiction only over final decisions of district courts that end the litigation on the merits and leave nothing for the court to do but execute the judgment.12 A narrow exception permits immediate appeal of collateral orders that conclusively determine the disputed question, resolve an important issue completely separate from the merits of the action, and are effectively unreviewable on appeal from a final judgment.13
No. The order denying the motion to disqualify meets the first Cohen requirement because it conclusively determines whether respondent may continue representation.14 It arguably satisfies the second requirement of resolving an issue separate from the merits.15 It fails the third requirement, however, because the denial is reviewable after final judgment on the merits, at which point the court of appeals may vacate the judgment and order a new trial if it finds prejudicial error.16 Petitioner urged only that respondent might shape the claims in a way that would increase petitioner's burden, yet supplied no concrete example of indelible taint or irreparable harm that could not be remedied on post-judgment review.17
Orders denying motions to disqualify opposing counsel in civil cases are not appealable under 28 U.S.C. § 1291 prior to final judgment.18
Related opinions on this issue
Justice Rehnquist concurred in the result only. He agreed with the majority that an order denying disqualification is not effectively unreviewable on appeal from final judgment, making that dispositive of the appealability issue.19 However, he objected to the majority's unnecessary discussion of whether the order conclusively determines the disputed question under the first prong of the Cohen test.20
Rehnquist noted that in Cohen, the order was a final disposition of a claimed right, unlike orders subject to reconsideration, and that recent cases like Coopers & Lybrand and United States v. MacDonald emphasized that orders subject to revision are not appealable.21 He pointed out that the district court remains free to reconsider its disqualification decision at any time, and in this case, the issues regarding respondent's theories of liability might become clearer as trial progresses, allowing a later motion when prejudice can be better gauged.22
Whether a court of appeals may reach the merits of an appeal from a nonappealable order and make its decision on appealability prospective only?23
The finality requirement of 28 U.S.C. § 1291 is jurisdictional. When an appellate court determines that an order does not fall within the statute, its inquiry ends and it lacks discretion to consider the merits; jurisdictional rulings may never be made prospective only.24
No. Because the disqualification order is not appealable under the Cohen doctrine, the Eighth Circuit lacked jurisdiction over the appeal.25 Although the court overruled its prior precedent and reached the merits solely in fairness to the appellant in this case, that approach was improper.26 Applied to the established facts, the Eighth Circuit's en banc decision affirmed the district court's pretrial order permitting respondent to continue after obtaining consents, yet the jurisdictional defect required dismissal rather than any prospective limitation on the new rule.27
The Eighth Circuit lacked authority to decide the merits, so its judgment must be vacated and the appeal dismissed for want of jurisdiction.28