Why is Obama allowed ‘executive discretion’ on immigration, but Trump isn't?

As House Democrats vote Tuesday to stop President Trump’s emergency declaration on the southern border, congressional Republicans should ask themselves: Why is it that every other president is permitted by courts to exercise “executive discretion,” and yet Trump isn’t?

A New York Times report on Monday set up the scene for weak-willed Senate Republicans, writing that, “The [Democrat-controlled] House’s vote on a declaration of disapproval will force Republicans to choose between the congressional prerogative over federal spending established in the Constitution and a president determined to go around the legislative branch to secure funds for a border wall that Congress has refused to grant.”