During the president’s State of the Union address, Colorado Sen. Mark Udall normally would sit with his fellow Democrats. Sitting by party affiliation is the custom during the joint session of Congress convened for the event.

But there is nothing that mandates that seating arrangement, and Udall plans to “take a right” and sit on the GOP side. He predicts “there will be a lot of senators who join me.”

It is a good idea. Partisan seating fosters demonstrations of support or opposition for the cameras. Mixing up the seating could result in a bit more comity and conversation between the parties – or at least less grandstanding. Besides, it would cost nothing.

Udall’s hope is to symbolically show the two parties can work together for the good of the nation. At last count, 21 senators have agreed to go along, including Republican Sen. John McCain.

No one thinks this will end Washington’s bitter squabbling. But no one has yet come up with a reason it might hurt.

Rep. Scott Tipton should join McCain and find a seat among Democrats just this once.