A Thought Experiment

Picture the following scenario:

The people of Mexico have decided that they are fed up with their government.  Protests begin, grow, and take over Mexico City.  Violence erupts between the government and some of the protesters, and a number of people are killed.  Eventually the government comes forward with a number of measures to try to placate the protesters, including the ouster of President Enrique Peña Nieto.  Tension remains in the air as embedded powers struggle to maintain their grip on the government while various factions within the protest movement also position themselves to take control.  Among those various factions are large groups that want Mexico to remain allied with the United States and are committed to NAFTA.  Also among them are groups who aim to ally Mexico closely with Cuba, and perhaps also the Chavistas in Venezuela and Evo Morales in Bolivia.  The situation is highly uncertain and unstable.

In this scenario, how would the United States react?  I think it’s a near certainty that they would mobilise troops toward the Mexican border.  I also think that there’s a small but real possibility that they would send troops into Mexico, especially if the violence escalated.  And I think there’s a pretty high probability that they would try to find other means of assisting the pro-U.S. faction within the opposition; “other means” would be actions like supplying arms or money to the U.S.-allied opposition or going around in the international community very loudly talking up the legitimacy of those factions and attacking the Cuban-allied faction.

And if those things happen, I would judge them like this:

I would say that the United States was behaving in a rational manner by mobilising troops, as it has a legitimate interest in protecting the security of its borders and was understandably concerned about the possibility of violence spilling over.  I would also say that their right to use force ends at self-defence and that any actions taken to promote a violent victory by their allies would be unacceptable.

I think these are the kinds of things that are worth keeping in mind when reading stories like this one.