Federal habeas courts are generally barred from overturning state convictions based on "new" rules of constitutional law announced by the Supreme Court after the state conviction became final. The justification for the Teague rule is that it respects the finality of state decisions and thus promotes federal-state comity. That justification does not apply in state post-conviction proceedings. Thus, the ACLU argues in its amicus brief, state courts should be free if they choose to reverse unconstitutional convictions even in circumstances where the federal courts could not.