until you are. Legal resident aliens, with their green cards, are welcome in our country.

Non-citizens can join the U.S. military, provided they meet certain eligibility criteria. Generally, lawful permanent residents (those with a Green Card) are eligible to enlist in the military. However, non-citizens typically cannot become commissioned officers unless they obtain U.S. citizenship.
The military offers pathways for non-citizens to gain citizenship through service, under specific programs. For example, the Military Accessions Vital to National Interest (MAVNI) program (when active) allows certain non-citizens with specialized skills to enlist and fast-track their citizenship process.