President Trump says he supports more legal immigration based on merit. If he means it, he should scotch a mooted labor regulation that would restrict temporary visas for high-skilled foreign graduates of U.S. universities.

“I want people to come into our country, in the largest numbers ever, but they have to come in legally,” Mr. Trump said in his State of the Union address, adding “we need people in our country because our unemployment numbers are so low.”

Excellent...