Humberto Leal, 38, received lethal injection for the 1994 murder of Adria Sauceda. She was fatally bludgeoned with a piece of asphalt.
Leal was pronounced dead at 6:21 p.m.
Leal moved with his family from Monterrey, Mexico, to the U.S. as a toddler. Police never told Leal following his arrest that he could seek legal assistance from the Mexican government under an international treaty and his case had prompted appeals on what it could mean for other foreigners arrested in the U.S. and for Americans detained in other countries. His appeals lawyers said such assistance would have helped his defense.
The argument was not new. Texas, the nation's most active death penalty state, has executed other condemned foreign nationals who raised similar challenges, most recently in 2008.
Leal's appeals, however, focused on legislation introduced last month in the U.S. Senate by Vermont Democrat Patrick Leahy. Leahy's measure would bring the U.S. into compliance with the Vienna Convention on Consular Relations provision regarding the arrests of foreign nationals and ensure court reviews for condemned foreigners to determine if the lack of consular help made a significant difference in the outcome of their cases.
President Barack Obama's administration took the unusual step of intervening in a state murder case when Solicitor General Donald Verrilli Jr. last week joined Leal's appeal in asking the high court halt the execution and give Congress at least six months to consider Leahy's bill.
"The legislation would give Mr. Leal an opportunity to demonstrate that with consular assistance, he likely would not have been convicted, let alone sentenced to death," Sandra Babcock, a Northwestern University law professor and one of Leal's lawyers, said.
Leal's attorneys had the support of the Mexican government and other diplomats who believed the execution should be delayed so his case could be thoroughly reviewed. Some also warned Leal's execution would violate the treaty provision and could endanger Americans abroad.
Measures similar to Leahy's have failed at least twice in recent congressional sessions. The Texas Attorney General's office, opposing the appeals, pointed to those failures in its Supreme Court arguments, saying history had validated that "legislative relief was not likely to be forthcoming."
Stephen Hoffman, an assistant attorney general, said the request for a reprieve to extend through the end of the current congressional term next January was audacious and that evidence pointing to Leal's guilt was strong.
"At this point, it is clear that Leal is attempting to avoid execution by overwhelming the state and the courts with as many meritless lawsuits and motions as humanly possible," Hoffman said., said. "Simply put, a bill is not federal law.... And because most bills introduced never become law, it is altogether unsurprising that bills are not afforded legal effect."