Illegal aliens aren't joining the military because they are willing to lay down their lives for America. They are joining the military for all the benefits. If they get killed in the process that's no different than the risk they take illegally crossing the border. These people have no allegiance or loyalty to America or the rule of law. They grow up and live in cultures steeped in corruption and that is what they bring to the US. It doesn't work the other way, they don't become patriotic law abiding Americans.
Going back to my post, a green card signifying being in this country legally is needed before being accepted. I said nothing about illegals joining. If they are in the country legally,join the military, serve their time,have a clean record, then I think they deserve citizenship. Semper Fidelis