Mr. Cantor, like most politicians, was less successful than Ronald Reagan in conjuring an illusion of distance from this compromising scrum, and this cost him his job on Tuesday. But he’s like Reagan in one way: At the end of a long career, he probably would have been satisfied—very, very satisfied—to have delivered a tax reform that restored growth and dynamism to the private sector, with all its cordial spillovers for social harmony and America’s international influence.

Today a good tax reform would go a long a way toward health-care reform and is the only thing that would get within a country mile of a climate policy that might justify itself in cost-benefit terms. A good tax reform would validate a lot of otherwise questionable Republican political careers, including Mr. Cantor’s, which after 22 years had brought him almost to the House speakership.

Now we’ll never know. And the economics professor Mr. Brat, who says sound things about the need to flatten the tax code, remove loopholes and put price-tags back on health care where consumers can see them? He has a long hill to climb before he can dream of having an impact on the things he claims to care about. More likely, because of the bludgeon he handed a future opponent thanks to his stance against a necessary and useful immigration reform, he will never get close.