I think the troops would be better deployed along our Mexican border than in the Middle East/Afghanistan; the problem is that we really can’t afford either (and there are Constitutional issues with deploying them here). As far as deploying them in Latin America itself, that is an unwinnable war; if we had partners (as we had in Colombia more recently with the Uribe government, or with the military rulers during the Cold War) then it might work. Unfortunately, many of the Latin American governments today are leftists like our own.
Let me be very clear: I think that the Mexican government plays ball with us, or we simply declare Mexico vs US II. This is NOT about immigration. It is about cutting a cancer out of the world and doing it in a manner that is strong and clear.
Yes, I know no one has suggested this. But the economics have simply become too significant to ignore.
No problem with the Constitution, as long as we post troops on the Mexico-side of the border ;-)