The White House is supported by the U.S. State Department, former President George W. Bush, the United Nations and the Mexican Foreign Ministry, which said Tuesday the execution of Humberto Leal, 38, scheduled for Thursday, would violate international law.
The Texas Board of Pardons and Paroles refused Tuesday to stop Leal's lethal injection in Huntsville for the 1994 rape and killing of 16-year-old Adria Sauceda of San Antonio. The board also refused to commute Leal's death sentence to life in prison, the San Antonio Express-News reported.
Texas Gov. Rick Perry, a possible GOP presidential hopeful, could stay the execution for 30 days.
His office told the Express-News, "if you commit the most heinous of crimes in Texas, you can expect to face the ultimate penalty under our laws."
Texas state lawyers Tuesday told the Supreme Court appeals in Leal's behalf were without merit and intended only to delay the punishment.
The Obama administration asked the court Friday to put the execution on hold for as long as six months to give Congress time to consider a law that would require individual states to abide by an international agreement the country must follow, to inform arrested foreigners of their right to contact their consulates.
Leal's lawyers argue police violated the Vienna Convention on Consular Relations by not telling Leal he could contact the Mexican consulate after his arrest in the death of Sauceda, whose beaten nude body was found on a dirt road near a party she and Leal had attended.
Leal's lawyers argue the case's outcome might have been different if Leal had been allowed to get legal help from the Mexican consulate.
Leal, of Monterrey, Mexico, incriminated himself in statements made in police interviews. If he had contacted the Mexican consulate, he would have likely arranged for a lawyer who would have advised him to limit his statements, Leal's lawyers argued.
Mexican authorities were not initially informed of his arrest.
Leal's lawyers argued Sauceda was under the influence of drugs and alcohol at the party, was raped there and died accidentally after she fell on a rock with Leal nearby.
Executing Leal could harm "Americans abroad" and hurt relations with Mexico because the United States would be "demonstrating [lack of] respect for the international rule of law," U.S. Solicitor General Donald Verrilli argued in a 30-page brief.
"American citizens traveling abroad [could be denied] the benefits of consular assistance in the event of detention," the brief said.