How many countries will back Mexico if the US attacks it?

Answer 1

None, really. Many would protest, but all of them would chicken out, just as they did when the US attacked Iraq, even if such attack has been thoroughly seen as unjustified.

Such attack however, would be quite dangerous for the United States interests at home and abroad: Just for you to ponder, what do you think would happen if Iraq and Afghanistan were next door to the United States?

Right now America is suffering a huge economic debacle due to a war with a medium-sized country and a medium-sized insurgence. Iraq and Afghanistan combined have a population of some 58 million people, and an area of 1 million square kilometers (421,000 sq mi). Imagine what would happen if America attacked a country next door with twice the population (118 million) and twice the area (1.9 million sq km / 758,450 sq mi) and of which 12 million of its citizens live in America but happen to have family and friends in Mexico.

Imagine what would happen if only 1 million of such foreign nationals in American soil began to perform terrorist and sabotage operations due to the fact that a misdirected missile killed uncle Paco and auntie Rosa. Also, there are many Americans (from 100,000 up to 2 million) living in Mexico, many of who would be unable or unwilling to move back to the States in the face of such event, thus becoming probable collateral damage. Finally, in the event of a war with the US, Mexico would perform a policy called "scorched earth", which calls for burning down or destroying anything that could be of use to any invading forces thus effectively, destroying the possible cause of such war -- most probably oil, which is already being exported by Mexico into the US.