Extradition question, could this happen?

Question

ok so im a supporter of the death penalty for murderers, and what really pisses me off is, when the united states asks for a murderer to be extradited from mexico, mexico will agree but will require the United states to sign a pact saying that we will not seek the death penalty for the murderer. my question is, what if we promised to not seek the death penalty, got the guy back here then just, sought it. i mean whats mexico gonna do, invade us?

Answer 1

For some unknown reason, the US has placed much higher moral and behavioral expectations on itself as has the rest of the world.  There would be an international uproar. The libs would be disgusted that we broke a promise. Mexico and Canada would just keep our criminals instead of extraditing them.

Answer 2

Oh yeah that'd be the day!  

Answer 3

It would violate treaties, and would be bad for our reputation.

Also Mexico isn't the only country that does this... so if we break our word other countries would be less likely to cooperate with US police forces.