I have no knowledge of this area of law, but responsible press are saying he can deploy NG and Marines to defend federal property and employees without anything special.

Third time's the charm!

We tried that. Nothing has changed since then - if anything he has consolidated more power.

Republicans would have to lose a lot of seats for it to happen. Or, Trump would do something beyond the pale for the GOP. Hard to imagine what would make them change their minds on it. Probably not thousands of dead protesters.