Interesting. Not sure. You would need to be here (in the US) legally. Not sure you could be a foreign national and enlist in the military. Probably would need a good visa and green card. Although, I had a German national from WW II in my platoon a long time ago that was trying to get his citizenship. I have known two or three that had dual citizenships, Brazil/American, Canadian/American, and German/American. Try asking at our embassy, too. Does this help.