President Trump recently announced that he could "call a national emergency" to build a wall on the border with Mexico. Despite his assertions to the contrary, no national security crisis exists at the border. Rep. Adam Smith, D-Wash., has indicated that the president might very well be able to use his powers to build a wall. But even if Trump fails to deliver one more mile of poured concrete or steel slats with his ploy, the country would face significant harm from his imaginary emergency. Indeed, if he continues down this path, he may well create a real national emergency that will eclipse his fake one.