In strikingly similar cases Texas executed two people (Jose Medellin - from Mexico - on Tuesday night and Heliberto Chi - from Honduras - tonight) who were foreign nationals and were convicted (both were guilty, Medellin confessed, and multiple eyewitnesses identified Chi at his crime) of murder.
So, the thing is that in Medellin's case, the Supreme Court decided that without specific Congressional order of how to do it, there was no way for the government to force Texas to abide by the decision. Furthermore, The International World Court asked Texas not to let Medellin go, and not even not to execute him, but merely to take time doing due diligence to make sure that his rights under the Vienna Convention (allowing him to counsel from his home country) were not denied. Texas was having none of that, and that was best summed up in Texas Governor Rick Perry's comment: "The World Court doesn't have jurisdiction in Texas."
I'm not wholly against the death penalty - though every argument I have for it is emotional - but I am for due diligence to make sure that the accused had every single one of their rights before they were executed.
Heliberto Chi argued similarly, and he also pointed to a treaty that the US had with Honduras to make sure that their citizens were treated fairly, but overall, it's disappointing that Texas decided not to wait. If you want to finish them off, that's fine, but allow them to exhaust all of their rights beforehand.