(CN) - Mexican national Humberto Leal Garcia was executed by lethal injection in Texas on Thursday, shortly after the Supreme Court rejected President Barack Obama's plea to stay his execution in a bitterly disputed 5-to-4 ruling.
In 1994, Leal kidnapped 16-year-old Adria Sauceda, raped her with a large stick, and bludgeoned her to death with a piece of asphalt, a jury found a year later.
Garcia always maintained his innocence, and his defense team said that the forensic evidence relied on controversial and flawed "bite mark" analysis.
According to the Texas branch of the ACLU, Garcia found out from a fellow inmate that he had a right under the Vienna Convention to seek assistance and legal counsel from the Mexican consulate.
In 2004, The Hague determined that Texas had violated the rights of more than 50 Mexican nationals sitting on death row, the New York Times reported.
Since that time, many of Garcia's supporters have been less concerned with the question of his guilt or innocence, than with whether his execution would undermine the rights and safety of Americans detained abroad.
Such concerns were raised by the White House, Solicitor General Donald B. Verrilli, Jr., and former army generals and navy admirals, who urged the Supreme Court to delay until there could be a hearing to determine whether Garcia's due process rights were violated.
Sen. Patrick Leahy (D-Vt.) introduced a bill called the Consular Notification Compliance Act to mandate such a hearing, which the dissenting judges believed could be voted on by September. The stay, if enacted, would have lasted until January 2012.
Texas Gov. Rick Perry, a staunch supporter of the death penalty, rejected waiting for a possible future hearing.
Supreme Court Justice Antonin Scalia, writing for the majority, said that prospect future legislation cannot stay a prior death sentence.
"The Due Process Clause does not prohibit a State from carrying out a lawful judgment in light of unenacted legislation that might someday authorize a collateral attack on that judgment," Scalia wrote, adding later. "Our task is to rule on what the law is, not what it might eventually be."
Downplaying the "grave international consequences" warned about, Scalia wrote, "Congress evidently did not find these consequences sufficiently grave to prompt its enactment of implementing legislation, and we will follow the law as written by Congress."
In a statement, Sen. Leahy expressed his disappointment with the Supreme Court's decision and said he will keep pushing to pass the bill.
"This case is not an isolated instance; the issue of consular notification remains a serious diplomatic and legal concern," Leahy said. "Congress has a responsibility to ensure that the United States is meeting its obligations under the Vienna Convention on Consular Relations, and I will continue to work with Members on both sides of the aisle to enact this important legislation. The safety and well-being of U.S. citizens who study, work and travel overseas depends on it."
Scalia noted that a lower court found that "any violation of the Vienna Convention would have been harmless."
The Mexican government, in an amicus brief arguing for a stay, said otherwise, writing that the execution would "seriously jeopardize" its efforts "to continue working collaboratively with the United States on a number of joint ventures, including extraditions, mutual judicial assistance, and our efforts to strengthen our common border."
In his dissent, Justice Stephen Breyer wrote that "it is difficult to see how the State's interest in the immediate execution of an individual convicted of capital murder 16 years ago can outweigh the considerations that support additional delay, perhaps only until the end of the summer."
Breyer ended his dissent by listing the opposing voices the majority's decision negated.
"In reaching its contrary conclusion, the Court ignores the appeal of the President in a matter related to foreign affairs, it substitutes its own views about the likelihood of congressional action for the views of Executive Branch officials who have consulted with Members of Congress, and it denies the request by four Members of the Court to delay the execution until the Court can discuss the matter at Conference in September," Breyer wrote. "In my view, the Court is wrong in each respect."