Almost every time like the one we are currently living in involves police/military people having to decide where their loyalties lie. Sometimes it's with the people, sometimes it's with the regime. Very often it is different between different agencies (with the lowest-level ones tending to side with the people).

The US is such a patchwork (both organizationally and on in individual level for each cop) that I think there will be a big and chaotic variety. It could range from sheriff's departments headed by Trump-loyal sheriffs who are willing to go to war with city agencies who are trying to protect their people, all the way over to city cops who eventually start actively defending their cities against the feds who are trying to do obviously illegal things there. That last one hasn't happened yet but I think it may be right around the corner. Things are changing. Those city workers telling Kristi Noem to get fucked from being allowed to pee in Broadview City Hall, that stuff doesn't happen in a vacuum.