He cannot abide criticism in any form. He cannot stand being disagreed with. He is intolerant of anyone who refuses to obey and support him unconditionally. He can fire people. He can deprive them of a means to earn a living. I don't know if he can legally deport them but why does legal matter to anyone who is so obviously ABOVE THE LAW? And he can have them imprisoned or killed by any means necessary. His pal Putin has had dissidents poisoned/shot and some have just disappeared without a trace. Lotsa options for an invincible indestructible omnipotent prez. Choices choices choices. Nice to have.