Peggy McGuinness discusses the international and federalism legal issues over at Opinio Juris. Essentially, she notes, the issue comes down to federalism and the avenues of a domestic remedy:
The problem for Leal and others whose death penalty convictions were obtained following a clear and acknowledged violation of U.S. obligations under the Consular Convention is not a lack of clarity about consular law. The problem is the domestic remedy. There are only two institutions remaining that can provide one to Mr. Leal today: The U.S. Supreme Court, if it accepts the very strong argument of Leal’s attorneys and the Solicitor General that the Court should invoke its power under the All Writs Act to stay the execution until the proposed jurisdictional and remedial statute (the Consular Notification Compliance Act) is adopted by Congress, or Governor Perry.