Cruz has made one completely unintended contribution to the fortunes of his party. It is likely that Republicans will look back on the 16-day government shutdown he forced in October as a liberating loss. The tea party coalition that rose to prominence in the 2010 election got precisely what it wanted and demanded. It promised wonderful things to follow. The outcome? Republicans of every ideological stripe have run in horror from every subsequent budget confrontation. The shutdown was either a random yelp of protest or a fundraising stunt for tea party groups. But it could claim no credible, positive relationship to the electoral prospects of the GOP.

Political movements that regard winning as a distraction tend not to win and eventually alienate the political parties they inhabit. After the shutdown, Republican leaders immediately seemed less intimidated by the purity caucus. (“They’ve lost all credibility,” House Speaker John Boehner said of tea party groups.) The U.S. Chamber of Commerce and a number of Republican donors resolved to aid electable Republicans in primaries. Tea party challenges have fizzled in Kentucky and Texas. They are fading in Kansas, Tennessee and South Carolina. And even in Mississippi — where Sen. Thad Cochran is a vulnerable incumbent — the tea party insurgent struggles to explain his recent skeptical reaction when asked about Katrina relief funding. There are few libertarians after hurricanes.