Gov. Mark Dayton’s attempt to horsewhip the House Republicans back to the negotiating table on the tax bill failed in its first legal challenge this week. Ramsey County District Judge John Guthmann ruled on Wednesday to restore the funding for the legislative operations that Dayton had stripped from the state budget bill last May.

The judge stated that Dayton clearly crossed the constitutional line of separation of powers by effectively eliminating another branch of government. That’s not what the line-item veto is meant for, he said.

One doesn’t need to be a legal scholar to see how problematic that kind of political hardball can be. No other governor has tried to do anything like that.

Dayton claims it all has to do with the “fiscally irresponsible” tax cut bill that he signed, unwillingly, because the Legislature had stuck a clause in another bill that if he didn’t sign the tax bill, the state Department of Revenue would be defunded.

Instead of overreaching on the line item veto, the governor should have vetoed both the tax bill that he didn’t like, and the bill containing the poison pill about the Revenue funding. Then he could have said, “I’m not going to put up with those shenanigans. Now let’s sit down and reason together.”

But he didn’t. Now Dayton is planning to appeal Judge Guthmann’s decision to the Minnesota Supreme Court, where it is likely to get shot down just as quickly as it was in Ramsey County District Court.

Dayton should accept the verdict, and accept that he lost on the tax bill, and get on with trying to manage the state.