I'm still puzzled about the implications of a citizen of one country being in the army of another country. What would happen if the USA decided to invade Canada? Does the USA take recruits from all countries? At least the French keep their foreign recruits in a separate unit, the Foreign Legion.

The IRA at one point, prior to the Troubles blowing up, used to rely largely on people who had done their training in the British Army. I wonder how many Al Qaida trainees there are in the US military?