Karl Penhall from CNNI did a series on the Columbian drug trade, and interviewed members of of the cartels. Apparently Columbia signed an extradition treaty with the US, and members of the cartel can be extradited to the US! They now wholesale the Drugs to Mexican cartels, but still control European operations.
There was talk of a North American Union consisting of Canada, the US and Mexico during the Bush administration, but drug violence along the border may have put that on the back burner. I read somewhere that Bush Sr. dreamed about an economic union of all the Americas.
NAFTA did bring American agribusiness into Mexico for the cheap labor, and, no doubt, hurt Mexican farmers. It also hurt migrant workers in the US. They were getting $9 an hour in the US but were paid $11 a day when their jobs went to Mexico.
I would not be surprised if the Bush administration considered military action in Latin America, but I don't think it would fly with Obama. Any type of subversion would not work in most of South America because a majority of these countries lean to the left or, at least, are oriented toward democracy.
I am concerned about Central America, because multinational agribusiness has a long history there, and they were fomenting revolutions before the US had an intelligence service.