President Donald Trump has declared a national emergency to fund the wall along the nation’s southern border. Speaking in the Rose Garden, Trump said there was an emergency at the border which could only be fixed by building a wall.

House speaker Nancy Pelosi and Senate minority leader Chuck Schumer had said before Trump’s address that they would take action “in the Congress, in the Courts, and in the public” to oppose the President’s declaration. Pelosi and Schumer assert that Trump’s decision to declare an emergency is unlawful and would “shred the Constitution” by circumventing Congress’ power to control spending.

Declaring a national emergency is certain to be systematically attacked in the hostile media as an abuse of presidential power that violates both the Constitution and power of Congress. It is now up to Trump’s legal team to prepare for battle. The President acknowledged that the Administration expects to be sued over the national emergency declaration: “And we will possibly get a bad ruling [in the courts] . . . and then we’ll end up in the Supreme Court.” Legal proceedings could hold up the actual construction of the wall for months.

Responding to a reporter’s question, Trump made a careless remark effectively conceding that there was no actual emergency to justify his extraordinary measure: “I could do the wall over a longer period of time,” he said. “I didn’t need to do this, but I’d rather do it much faster.” That answer is certain to complicate his legal case. The emergency is real, but Trump’s performance unfortunately lacked sureness of touch.