MELISSA BLOCK, HOST:
And for those wondering why so many Republicans turned against their own leader tonight, a big part of the answer lies in their next election, as David alluded to. It's not Democrats they're worried about. As Tamara Keith reports it's other Republicans challenging them in their next primary.
TAMARA KEITH, BYLINE: House Speaker John Boehner argues this isn't a tax increase. But a number of conservative groups have come to a very different conclusion.
BRENT BOZELL: Fiscal conservatives will not stand for this.
KEITH: Brent Bozell is chairman of a group called ForAmerica. He was speaking at a press conference yesterday outside of the Capitol warning House Republicans there will be consequences if they line up behind the speaker.
BOZELL: A whole lot of members who thought they were safe and who thought they could get away with this will lose in their own districts.
KEITH: What he's talking about is members getting primaried. It's not a real verb, but it is a real threat with well-funded outside groups like the Club for Growth saying they'll be watching these votes closely. The group's Barney Keller says how Republicans vote now could set the stage for the 2014 primary season.
BARNEY KELLER: One thing we found is that the only thing that motivates members of Congress is the fear of losing their jobs, and that's we - that's the stick we try and use to try and get them to vote for pro-growth policy.
KEITH: It's a stick they have used quite effectively in the past. The club got involved in 17 primaries this year and their candidates won 12 of them. Kansas Republican Tim Huelskamp says he'd fully expect a challenge from the right.
REPRESENTATIVE TIM HUELSKAMP: If I went home and told them after taking a pledge not to raise taxes and voted for that, I would certainly deserve a primary opposition, and my wife might be the first one to run.
KEITH: Still, many Republicans appear to be choosing pragmatism over ideological purity. Tom Cole is from Oklahoma and has been a vocal proponent of the Plan B strategy.
REPRESENTATIVE TOM COLE: I say this as a guy that used to be a political consultant: If I can't beat somebody challenging me because I protected the tax cuts of almost every single one of my constituents, then I'm not a very good politician. I mean, I'm not worried about me. I would invite this fight.
KEITH: For most of today's House Republicans, this is the first time they've ever been asked to take a vote that smacks of raising taxes. The last time Republicans were in that position, George H. W. Bush was president. Sarah Binder is a senior fellow at the Brookings Institution. She says these members just won elections with a strongly anti-tax message, and it's something they believe in deeply.
SARAH BINDER: To the extent it could be framed as violating pledges and raising taxes, it puts these members in a very tough position personally and ideologically and electorally. And I think they're reluctant not just for electoral pressures but because of who they are and what they stand for. They don't want to renege on where they think they've already placed themselves.
KEITH: They'll find out how real that electoral pressure is in six months or a year when the 2014 primary season begins in earnest. Tamara Keith, NPR News, the Capitol.