I presume that the administration will therefore call for “training exercises” in US cities on a regular basis?

The day is not over yet. Be on the lookout for loyalty tests that would surface which officers might be inclined/friendly to go against posse comitatus.

“Te estoy llamando América
Pero no me respondes
Te han desaparecido
Los que temen la verdad”

English - “I'm calling you America
But you don't answer
You have disappeared
Those who fear the truth”