...there's a school of thought that says this is really Trump's best way out. He can declare himself a strong leader and a big winner while essentially punting the decision to the courts, allowing the government to reopen while the legal issues are hashed out. There is considerable disagreement as to whether or not he will ultimately prevail.

Yale law professor Bruce Ackerman writes in the New York Times that if Trump goes through with using the military for this purpose he would be committing an unconstitutional abuse of his power as commander in chief, adding that if troops obey his command, they'd be committing a federal crime. But according to this chilling article by Elizabeth Goitein in The Atlantic, any president's ability to evoke these sorts of emergency powers is practically unfettered. After all, Congress has delegated these powers to the president for decades -- and for decades presidents have pushed the envelope in dozens of different ways. This time we may finally have a president who is willing to do it for blatant political purposes and dare anyone who opposes him to do something about it.

There is a long history of judicial deference to the executive branch on national security issues. It will ultimately be up to the five conservative Supreme Court justices to decide if they have the power to step in when the president is clearly concocting a fraudulent emergency for his own reasons. I wouldn't bet money on them making the right decision.

We can be sure that Democrats in Congress will raise a fuss but unless they are willing to push for an article of impeachment for abuse of power (which they clearly have a right to do) the best we can hope for is that the clock runs out on his term before the court produces an opinion. Validating this action would set a very bad precedent.