ThanQ. Very intredasting.
That something could be the federalization of the NG and deployment along the border to completely lock it down. This would stem the tide of people crossing because we'd simply not let them in.
Posse Comitatus applies to Citizens and not to foreign invaders along the border.
The law of catch and release applies to ICE and other civilian agencies. It does not and cannot apply to the Army in this case.
Fully constitutional. Fully with legal precedent.