Just did some googling on Posse Comitatus & how Federal troops can be deployed against the citizenry.
Nearly every scenario involves actual violence: riots, insurrections, & attacks on Federal property beyond the control of the National Guard, to trigger the sending of Federal forces & the use of detention camps.
In other words, the state of Alabama passing a law affirming the right to bear arms should not result in Birmingham being seized & occupied by the 82nd Airborne Division.
Or, a plurality of states pass resolutions declaring that state law enforcement will not assist Federal gun confiscation. Preezy federalizes the National Guard in those states & orders Guardsmen to start going door to door.
Eighty percent of those Guardsmen suddenly go on sick call.
And the other 20% are picked off from ambush.