The forces of political nihilism not only remain alive and well within the Republican Party, but they are on the rise. Witness the way they shook Washington on Tuesday by removing from power Eric Cantor, the House majority leader, who had been one of the most implacable opponents to the reform of immigration, health care and taxation. His crime (in addition to complacent campaigning)? He was occasionally obliged, as a leader, to take a few minimalist steps toward governing, like raising the debt ceiling and ending a ruinous shutdown.

For that he was pilloried in his Virginia district by a little-known resident of the distant extremes, David Brat, whose most effective campaign tool was a photo showing Mr. Cantor standing next to President Obama. By falsely portraying the seven-term incumbent as just another compromiser, just another accommodationist to the power of big government, Mr. Brat managed the unimaginable feat of bringing down a majority leader in a primary, and by double digits.

“Cantor is the No. 1 cheerleader in Congress for amnesty,” Mr. Brat wrote in The Richmond Times-Dispatch on Friday. This is utter nonsense. More than anyone else in the House, including Speaker John Boehner, Mr. Cantor was responsible for the chamber’s refusal to vote on the Senate’s immigration bill. He personally refused to allow a vote on an amendment to give legal status to undocumented immigrants who serve in the military.

He did publicly muse about the possibility of a bill that would provide a path to citizenship for children brought to the country illegally, perhaps aware that the long-term future of the Republican Party requires the support of some Hispanic voters. But after voting down the real Dream Act in 2010, he never brought his own bill to the floor. He sent fliers around his district saying the “Obama-Reid plan to give illegal aliens amnesty” would ignore the rule of law and “reward people for illegal behavior.” He was nonetheless called “amnesty-addled” by one of Mr. Brat’s talk-radio surrogates.