Foreign murder suspects have no rights in U.S. federal courts to challenge their convictions on the grounds they were improperly denied legal help from their consulates, the Supreme Court was told Monday in a case testing the effect of international law in death penalty cases.

Justices heard arguments in the case of Jose Medellin, who says his rights under a U.S. treaty were violated when a Texas court tried and sentenced him to death in 1994 without giving him consular access.