The first positive note is that the president got anything at all for a barrier. Remember that the Democratic position, expressed repeatedly by Speaker of the House Nancy Pelosi, was that Trump would get nothing for a barrier — and by “nothing,” Democrats meant “nothing.” That is precisely what the president got in the measure to end the government shutdown. Pelosi even famously declared Trump’s wall proposal “immoral.” In the end, though, the Democratic House approved — with 300 votes, including Pelosi’s — enough money to build 55 miles of the president’s proposed barrier…

But the president starts with the $1.375 billion that Congress has appropriated specifically for barrier construction. It is real money, ready to be spent. And in addition to funding the construction of a barrier, the appropriation also argues in favor of the national emergency. Trump is not declaring a national emergency to undertake some action that Congress has expressly forbidden. Indeed, he proposes to do something — building a barrier — that Congress has specifically approved, even though he wants to do more of it than Congress has included in the new legislation.

In a recent article, Berkeley law professor and former Bush administration Justice Department official John Yoo pointed to Congress’ acts as a difference between the Trump emergency declaration and the famous Supreme Court Youngstown decision, in which the Court stopped President Harry Truman’s proposed seizure of steel mills