There is no number of foreigners that is unacceptable to sacrifice for a middle class livelihood. Anti-cop because they can imagine a scenario where a cop inconveniences them. These principles don't apply to the Waffen SS because they can't imagine a soldier personally inconveniencing them and, of course, foreigners aren't really humans.
1974 Revolution in Portugal was mostly done by volunteer soldiers and officers, so this option is possible (if unlikely in USA). But you would still need soldiers and officers to train your leftist militias or you would get steamrolled.
I hope all this shit around Ukraine and Taiwan would lead America to reestablish draft. It would be really useful for the Left.
The draft would definitely accelerate things, which could be good or bad...