What happens if President Trump decides to ignore a valid court order? Will that instigate a constitutional crisis? Good question.
As it turns out, if he does so, it wouldn't be the first time that a President has run afoul of the courts.
Andrew Jackson did it.
Abraham Lincoln did it.
I'm sure that better minds than mine are looking into the question. Certainly, the executive is not always right, but neither are the courts. This is a time for serious people to be in charge.