Enlisted Marine Corps ranks are broken down into three levels, Junior Enlisted, Non-Commissioned Officers, and Staff Non-Commissioned Officers. As a Marine moves up the ladder his or her responsibility and contribution to the mission increases.
Also, children born abroad to two non-citizen nationals or to one alien parent and one non-citizen national parent are eligible for non-citizen national status. This is so rare that the State Department does not even issue a certificate for it. Non-citizen nationals are delineated as such in their passports.
Non-US citizens can obtain Global Entry, but enrollment is extremely limited. Aside from US citizens and permanent residents, Global Entry is available to citizens of German, the Netherlands, Panama and South Korea, as well as to Mexican Nationals.