The state of Texas is hours away from defying the White House and international law by executing a Mexican national, and the Supreme Court could step in today to stop the execution.

Humberto Leal, 38, is awaiting a ruling by the U.S. Supreme Court on whether to block his lethal injection in Huntsville. He was sentenced to die for the 1994 rape and murder of 16-year-old Adria Sauceda of San Antonio.

The appeal contends that authorities never told Leal after his arrest that he could seek legal assistance from the Mexican government under an international treaty, and that such assistance would have aided his defense. Leal moved to the U.S. as a toddler.

Leal’s attorneys have support from the White House, the Mexican government and other diplomats who believe the execution should be delayed so his case can be thoroughly reviewed.

“There can be little doubt that if the government of Mexico had been allowed access to Mr. Leal in a timely manner, he would not now be facing execution for a capital murder he did not commit,” Leal’s attorneys told the Texas Board of Pardons and Paroles in a clemency request rejected Tuesday. “Unfortunately, Mexico’s assistance came too late to affect the result of Mr. Leal’s capital murder prosecution.”

I would imagine that the perspective of the White House is that this is less about Leal than the precedent it sets for US nationals abroad. The Vienna Convention on the arrest of foreign nationals would be violated by this execution, although it wouldn’t be the first time. In 2008, in a separate Texas case, Jose Medellin was executed after conviction for murder, even though his lawyers raised the Vienna Convention issue as well. The Leal case has been more publicized, and goes back to a 2005 ruling in the International Court of Justice. They said that Leal needed a new hearing to see if his consular rights were violated by being denied access to the Mexican consulate at the time of his arrest. George W. Bush agreed with that ruling, but the Supreme Court negated it.

The hopes that they will stay the execution of Leal today rest on the notion by the US solicitor general that Congress has pending legislation to allow this kind of consular rights review, bringing the country in line with the Vienna Convention. I’m wondering if the solicitor general has seen Congress operate lately. There’s no such thing as “pending” legislation there anymore. In fact, this law has been introduced and failed twice before. So far, lower courts rejected the stay.

Texas Governor Rick Perry appears to have no interest in a reprieve while the international issues are sorted out, especially given that he may run for President, and wouldn’t want anything resembling compassion on his record heading into a GOP primary.

My guess is the execution will go through today, but we shall see.