I think a lot of Mexicans and Americans with Mexican bloodlines in the U.S.A. would join up with Mexican Army. I have met a few guys that have told me this when I asked them this very question. This always puzzled me since they where here in the United States and members of our military?
I think we would have one hell of a insurgent probelm with a lot of double agents. Not to mention a chunk of our own troops pulling a Benedict Arnold. Talk about a bad situation.