I think a border wall could do some good, though it certainly isn’t the most effective possible way to bring illegal immigration under greater control. And I think opposition to the wall has gotten completely out of hand and ridiculous. But there are lots of things I think Congress should do that it has not chosen to do. That’s too bad. I wouldn’t want the president to just do them anyway.

We do not need to tie ourselves in knots around the fine legalities to see that taking the kind of action President Trump has said he is considering would violate the structure of our Constitution. It could be that a federal judge would not have to throw it out. But Congress and the public should deem it a constitutional violation and look for ways to prevent or reverse it. For members of Congress in particular to fail to do so, let alone to encourage the president to go around Congress and spend money that has not been appropriated, is a dereliction of Congress’s duty. It is unfortunately the latest of many.