Misusing emergency powers will open the door to further such abuses by this president—or a future one, writes Elizabeth Goitein.

Invoking presidential emergency powers gives the president the ability to go around Congress and unlock federal funding to crack down at the border.

As active-duty U.S. soldiers began moving toward the nation's southern border to confront what President Donald Trump called "a national emergency," much is still unclear about their mission, including whether they would be armed,