In the Era of Obama anyone could go to US ARMY, Green card was not a requirement but you would get citizenship after you get recruited and have your 3 months training completed. Now, Mr Trump changed the rule. Only Green Card holder or citizen can go to army. And the sad part is those who are already in the army and have not got their citizenship yet, will not be granted citizenship and shall be deported if they wont get any other status once they will be thrown out of army.