Legal Aliens with a green card was allowed in my squadron. She did everything required to be a citizen. It took her two years. That is acceptable. BTW, the missions are secret.
Illegal aliens are to be deported. Seasonal immigrants were allowed with documentation. ca. 1983
Don’t have problems with legal aliens. I served with them, too. But the title is “Illegal Immigrant who serve in the Military deserver Citizenship.”
And I say that, if an illegal alien makes it into the US Armed Forces, then you have a SERIOUS security breach.