The vast majority of the world’s countries have outlawed the use of the death penalty. (Source: Amnesty International.) The United States, of course, is not among those countries. Mexico, however, is among those countries. However, that may be changing.
According to Marion Lloyd of the Houston Chronicle, “Mexican legislators are opening the way for what promises to be an emotional debate on whether to reinstate the death penalty.” The proposed reinstatement would be applied to kidnappers who kill their victims.
The impact this might have on extradition between the two countries is pretty stark, as Llyod points out: “A 1978 extradition treaty with the United States allows Mexico to deny extradition if a suspect faces the death penalty in another country.” Indeed, this is the case. In fact, until recently, in extradition requests, the United States had to agree not to even impose a life sentence because the harshest penalty used to be a maximum of 30 years in prison; that changed in 2005 when Mexico approved certain life sentences. (Source: BBC, among others.)
Changing the law in Mexico to allow the death penalty could potentially remove the requirement that the United States seek at most life imprisonment for extradited individuals.
And just to be clear: most extradition treaties between the United States and other countries allow those countries to deny extradition if the death penalty is sought. (This leads to the United States promising not to seek or impose the death penalty if the individual is extradited.) Those same treaties also allow the United States to refuse extradition on the same basis, but the United States rarely has such qualms, even if the individual wouldn’t be subject to the death penalty in the United States. (See, e.g., Prasoprat v. Benov, 421 F.3d 1009 (9th Cir. 2005) cert. denied 546 U.S. 1171 (2006) (individual can be extradited to Thailand for drug crimes even though he faced the death penalty, which would not imposed in the United States).)