AS WITH many other things that happened in the 1960s, the origin of the conflict between the governing wing and the ideological wing of the Republican Party is a bit fuzzy. Most date it to 1964, the year Barry Goldwater ran for president on a small-government platform and won only six states. The Republican civil war, as it is known to politicos, has now lasted five years longer than the cold war. It would be foolish to attach too much importance to a single battle. Even so, the budget vote in the House of Representatives at the close of 2013 marked an important shift.

By voting for the deal, House Republicans defied the unelected bit of the party—which resides in think-tanks, lobbying organisations and political action committees—by 169 votes to 62. In the run-up to the vote, lobby groups such as the Club for Growth, which awards congressmen points for voting against tax increases, and Heritage Action, which campaigns for fiscal and social conservatism, had urged Republicans to reject the deal on the ground that it was a spending rise in disguise. “I don’t care what they do,” John Boehner, the House Speaker, told a press conference after the vote. On December 17th the bill moved forward in the Senate, as 12 Republican senators voted not to filibuster it. It is now highly likely to pass.

Until recently, conservative pressure groups appeared to hold more sway over House Republicans than Mr Boehner did. Many congressional Republicans feared that they would fund primary challengers in their districts. Primary My Congressman, a website run by the Club for Growth’s political action committee, is currently running an advert that invites the viewer to “click here to defeat Mike Simpson”, a Republican congressman from Idaho who is one of Mr Boehner’s allies. Because few voters on either side turn up to primaries, an insurgent candidate can sometimes unseat an incumbent with only the support of a small but motivated clutch of voters.

The groups that seek to harden congressional Republicans against compromise with the other arms of government are cross about being pushed aside. “There are over 150 Republicans who just voted for a spending rise in exchange for minimal entitlement reform,” says Barney Keller of the Club for Growth. “They always use the same argument: that they have to be around so they can vote for the hard stuff later.” “The question is whether the Speaker will continue to say that conservative voters are not really welcome,” says Dan Holler of Heritage Action.

Yet these organisations have finite resources. They cannot back primary challenges against all congressional Republicans, so there is some safety in numbers. And their influence can seem greater than it really is. Most Republican congressmen cast conservative votes because they are conservatives, rather than because they are frightened of being primaried. Only 13 of the 232 House Republicans have declined to sign a pledge never to vote for a tax increase. Tax revenues as a share of GDP have fallen slightly over the past decade, according to the Congressional Budget Office. “Lots of these groups were set up to hunt RINOs [Republicans in name only],” says one veteran anti-tax campaigner. “But the truth is there are not many around now.”