This article shows what happens if Trump declares a national emergency. It's insane.
The moment the president declares a “national emergency”—a decision that is entirely within his discretion—more than 100 special provisions become available to him. While many of these tee up reasonable responses to genuine emergencies,
some appear dangerously suited to a leader bent on amassing or retaining power.
He could determine that any American inside the U.S. who offers material support to the asylum seekers—or, for that matter, to undocumented immigrants inside the United States—poses “an unusual and extraordinary threat” to national security, and authorize the Treasury Department to take action against them.
He could characterize sanctuary cities—cities that refuse to provide assistance to immigration-enforcement officials—as “conspiracies” against federal authorities, and order the military to enforce immigration laws in those places.
https://www.theatlantic.com/magazine...powers/576418/