It’s easy to see why Mitt Romney has had enough, the Editorial Board writes. It’s time for Utah voters to step up.

Nothing in Mitt Romney’s long political career became him like the leaving of it.

Romney’s announcement Wednesday that he was stepping aside after a single term in the U.S. Senate says a lot about Utah’s best-known and — outside the radical right wing of his own party — most admired politician. Much of it good.

And it says a lot about the state of politics in America today. A lot of it bad.

What happens next will be up to the voters of Utah.

Those voters will not only have a...