Whether the Michigan v. Long “plain statement” rule applies in federal habeas proceedings when a state court's decision ambiguously refers to a state procedural default.
Holding
Yes. A state procedural default bars federal habeas review only when the last state court rendering judgment clearly and expressly states that its judgment rests on that state procedural bar.
Reasoning
The Court traced the procedural-default doctrine in federal habeas to the adequate-and-independent-state-ground doctrine. On direct review, an adequate and independent state-law ground prevents federal review of a federal question; in habeas, an adequate and independent state procedural default generally prevents review unless the prisoner establishes cause and prejudice or a fundamental miscarriage of justice. In either setting, the central question is whether the state court actually relied on the state procedural ground.
Michigan v. Long supplies the answer to ambiguity about a state court's basis for decision. Under Long, when a state decision fairly appears to rest on federal law or to be interwoven with it, a federal court may address the federal issue unless the state court plainly states that its decision rests on an adequate and independent state ground. Caldwell v. Mississippi had already applied that approach to an unclear state-court reference to procedural default on direct review.
The same ambiguity problem arises in habeas cases. A federal habeas court should not have to infer a procedural ruling from uncertain language, inspect the record to determine whether default was argued, or undertake an elaborate inquiry into whether state law might have permitted the court to excuse the default. The state court, which is best positioned to identify its own ground of decision, can readily make its reliance on a procedural bar explicit.
The rule does not materially impair finality, comity, or federalism. A state court remains free to enforce its procedural rules and may reach the merits in the alternative without forfeiting the procedural ground, so long as it clearly and expressly invokes the bar as an independent basis for judgment. Requiring clarity also avoids federal courts second-guessing whether a state court silently chose to forgive a default.