True, even if their resident card had expired, they are still legal residents.
Someone from Mexico is not just going to wade cross the river and get into our Army and become a citizen.
He could not anyway, you must be a legal resident to join the military.
HOWEVER someone could come on a tourist visa/ student visa/work visa/ etc. and join the Army and become a citizen. I think this could be done...
Only if they presented a counterfeit resident card and the recruiter did not do his job in check it out.
How can they be legal if the card expires? Is the INS too backed up to reliably process applications for renewal of green cards?
Illegal aliens cannot serve. But under Clinton one of the Army biggies (who happened to be Hispanic American) floated a trial balloon in 1999. His idea was serve in the Army and you can become a US citizen...