The Supreme Court modified the Fifth Circuit's decision in a unanimous opinion authored by Justice Sandra Day O'Connor.

This "relitigation exception was designed to permit a federal court to prevent state litigation of an issue that was previously presented to and decided by the federal court" and is "founded in the well recognized concepts of res judicata and collateral estoppel."

Here, with respect to Chick Kam Choo's state-law wrongful death claim, the federal court's forum non conveniens determination that the case should be heard in Singapore rather than Texas did not preclude re-filing of the claim in Texas state court.

Thus, "the only issue decided by the District Court was that [Chick Kam Choo's] claims should be dismissed under the federal forum non conveniens doctrine.

"[2] Therefore, "whether the Texas state courts [were] an appropriate forum for petitioner's Singapore law claims [had] not yet been litigated, and an injunction to foreclose consideration of that issue [was] not within the relitigation exception.