On Jan. 22, a case with international implications was brought to a close with relatively little fanfare in the state of Texas. At 9:32 p.m., a Mexican citizen named Edgar Arias Tamayo was executed by lethal injection for killing Houston police officer Guy Gaddis in 1994. For 19 years, the Tamayo case has sparked national and international controversy. Although the case has now technically ended, Tamayo’s execution carries significant political implications on an international scale.

Tamayo and another man were in the backseat of Gaddis’ police car being taken from the scene of a robbery when Tamayo shot Gaddis three times in the back of the head and escaped. He was quickly recaptured and convicted. Tamayo spent the next 19 years on death row, waiting while Mexican and U.S. officials debated a case that would eventually reach the International Court of Justice in the Netherlands, the United Nations’ primary judicial entity.

Tamayo’s guilt was not debated; he was found shortly after Gaddis’s murder with the murder weapon and handcuffs from his previous arrest. The case’s controversy arises from the judicial and political implications of Texas’s decision to execute Tamayo. Tamayo’s defense argued that Tamayo had not been informed of his right to seek help from the Mexican consulate. Failure to inform Tamayo of this right is a violation of international law.

Moreover, during his trial, the court system refused to consider Tamayo’s lawyers’ assertions that he was mentally impaired and therefore ineligible for the death penalty. Both of these issues raised diplomatic tensions with Mexico. Adding to the tension was the fact that capital punishment has been illegal in Mexico since 2005 and out of use for decades before that.

To make matters worse, Tamayo was just one of 51 Mexican citizens who were not informed of their right to contact the Mexican consulate for legal help. Two other Mexican citizens have been executed by the state of Texas without being informed of this right, and twelve more are currently on death row. In Tamayo’s case, assistance by the Mexican government could have been invaluable, as it would have been easier to swiftly provide proof of Tamayo’s potential mental impairment with governmental help.

In the 19 years between Tamayo’s arrest and his execution, lawyers and advocates worked to prevent his execution. An organization called the Mexican Capital Legal Assistance Program, funded by the Mexican government, provided support for Tamayo’s lawyers.

Then in 2004, Tamayo’s case was brought before the International Court of Justice, along with 50 others, to be reviewed by that body as violations of the Vienna Convention on Consular Relations. Had Texas acted according to the Vienna Convention, put in effect in 1993, the case would have been eligible for review, due to the fact that Tamayo was unaware of his consular rights at the time of his arrest.

However, in 2008, the Supreme Court ruled that the federal government does not have the authority to force states to comply with international law. Texas therefore was able to ignore the Vienna Convention and punish Tamayo as it saw fit. The United States might be violating international law by executing Tamayo, but the federal government was powerless to stop Texas.

Both the U.S. government and international entities warned the state of Texas about the significance of their actions, and urged the state to reconsider. Texas officials insisted that Tamayo received as much legal process as he would have anywhere in the world. Lucy Nashed, a spokeswoman for Gov. Rick Perry of Texas, said of the case that “It doesn’t matter where you’re from, if you commit a despicable crime like this in Texas, you are subject to our state laws, including a fair trial by jury and the ultimate penalty.”

In spite of protests from Mexico and Secretary of State John Kerry, among others, Texas went forward with Tamayo’s execution.

Beyond human rights concerns, this case has wide reaching implications. By executing Tamayo and ignoring international law, Texas has set a precedent. As the Mexican government said before the execution went through, “If Edgar Tamayo’s execution were to go ahead without his trial being reviewed and his sentence reconsidered, it would be a clear violation of the United States’ international obligations.” Now U.S. officials are worried about the effect this decision could have on international relations. Kerry is concerned that because a U.S. state ignored the consular rights of a foreign national, other countries may do the same to American citizens that are detained abroad.

The Tamayo case raises age old questions of how much control the national government should have over states, as well as questions of how the U.S. will handle the current situation in its international policy. However these questions are answered, the fact of the matter is that a third Mexican citizen is dead in Texas without being fully informed of his rights.