White House budget director Mick Mulvaney has laid down a marker to the U.S. Senate.

Lawmakers shouldn’t vote on anything else, he said, until they vote once again on a Republican-authored bill to repeal and replace the Affordable Care Act.

There you have it. One branch of government is seeking to dictate to another branch how it does its job.

Hold on here, Mr. Budget Director.

Mulvaney ought to know better. He served in Congress before Donald John Trump tapped him as budget director. He used to fight on behalf of congressional prerogative, which is spelled out quite explicitly in that document called the United States Constitution.

The Constitution, furthermore, does not give the executive branch a single bit of authority over how the legislative branch conducts its business.

The term of art for more than two centuries has been that all three government branches are “co-equal.” That means they all have equal amounts of power. One branch cannot bully another branch.

“In the White House’s view, they can’t move on in the Senate,” Mulvaney said on CNN’s “State of the Union.” “You can’t promise folks you’re going to do something for seven years, and then not do it.”

Got it, Mick. Do not, though, try to push senators around by laying out their legislative priorities for them. That’s their job. It’s in the Constitution. Really … it is!