They've already found a solution: If your own citizens refuse to serve the military-industrial complex, then simply use foreigners:

Join the military, become a US citizen - https://apnews.com/article/army-air-force-recruiting-shortfa...

And the police: Bill to allow noncitizens to become Illinois police officers heads to governor’s desk - https://www.mystateline.com/news/local-news/bill-to-allow-no...

In addition to helping hit military recruitment targets, they also have less attachment to the American people, so they're less likely to revolt if they were deployed domestically.