Could Emergency Powers Build the Wall?

Trump says he can move without consent of Congress, but legal scholars are divided.

President Trump has threatened repeatedly to invoke emergency powers to build his wall on the southern border if Congress refuses to provide funds for it. By the time you read this, Mr. Trump may have announced this step in his address from the Oval Office.

I suspect most people’s first reaction is the same as mine: He can’t do that. But a deeper dive into the subject reveals a more complicated and contested state of affairs.

On...