I think it’d be more of a matter of presidential huevos gigantia than constitutionality. What would Lincoln have done? I mean besides locking the bastards up for treason.
:-)
Lincoln sent Union troops in to maintain order in Baltimore during the civil war.
That and other things led to the lines in the Maryland State Anthem
"The Despot's Heel is on thy Shore" (referring to Lincoln)
and
"Huzzah! She spurns the Northern scum" (I believe that line was finally removed in 1983.
Cheers!