Whether a federal habeas court may grant relief because a state trial court allegedly misapplied state evidentiary law in admitting evidence of a child’s prior injuries.
Holding
No. Federal habeas relief is unavailable for errors of state law alone; the federal court may review only whether the conviction violated the Constitution, laws, or treaties of the United States.
Reasoning
The Court reaffirmed the limited role of federal habeas review. A federal habeas court does not sit as another state appellate court to reconsider whether a state court correctly applied its own evidence rules. The relevant question is constitutional: whether the asserted error deprived the defendant of a federally protected right.
Thus, the Ninth Circuit erred to the extent it based relief on its view that California law did not permit admission of the prior-injury evidence. Even an incorrect state-law evidentiary ruling does not itself establish a basis for federal habeas relief.