A Republican civil war, which has simmered under the surface since the party's defeat in last November's presidential election, has now burst firmly into the open and pitted party leaders against each other.

Majority leader Eric Cantor's extraordinary vote against House speaker John Boehner in Tuesday's late-night vote in the House of Representatives may have prevented America from toppling over the so-called fiscal cliff, but it exposed the deep rifts that are destabilising a party once famed for its unity and discipline.

Cantor, 49, a self-styled "young gun" who hews relentlessly to rightwing conservative orthodoxy, is now pitted against Boehner, 63, a "country club" Republican whose pragmatic streak drives him to move the party to the centre in a bid to learn a lesson from President Barack Obama's second-term victory.

"Clearly, Boehner and Cantor are not bosom buddies. They never have been," said Professor David Cohen, a political scientist at the University of Akron.

That might be an understatement now. Just six hours before the crucial vote Cantor's spokesman, Doug Heye, sent a message on his Twitter account playing down rumours of a split. "Majority Leader Cantor stands with @speakerBoehner. Speculation otherwise is silly, non-productive and untrue."

However, Cantor then came out publicly against the bill, voting no, while Boehner himself – when tradition usually demands that a Speaker not vote – made a point of personally voting yes. "It is extraordinary for a speaker to vote," said Republican pollster Steve Mitchell, head of Mitchell Research and Communications.

The two men could come to personify a growing ideological split in the party. Boehner, with his fondness for golf and his year-round tan, has a reputation for old-school deal-making. He is seen as a master of backroom politics who is willing to sacrifice policy principle in favour of pragmatic politicking that improves the position of the party as a whole. As the Republican party seeks to come to terms with a demographic future that is seen as more friendly to Democrats, Boehner is viewed as someone who might steer the party away from the rightwing extremes that deter emerging voting blocs such as Hispanics and women.

Cantor, however, is a darling of that rightwing; popular with the Tea Party-backed politicians who swept into the House in the 2010 mid-terms and who still wield enormous power. Together with Mitt Romney's former running mate, Paul Ryan, and majority whip, Kevin McCarthy (who also voted no), Cantor co-wrote a 2010 book called Young Guns that sought to be a manifesto for an emerging generation of rightwing ideologues.

Cantor's high-profile "no" vote in the fiscal cliff debate now propels him to the front of the conservative movement. It is a bloc that sees Mitt Romney's failure to defeat Obama as an example of what happens when you run a moderate who has to espouse rightwing views he does not genuinely hold instead of a true conservative candidate.

It is a profound split in the party. While Boehner does not look immediately under threat when it comes to a fresh vote this week on his speakership, he does appear to now be in the minority in the House. Just 84 other Republicans joined Boehner in voting for the compromise bill to avoid the fiscal cliff, while 150 Republicans lined up behind Cantor in the no camp. "You have the whole notion of people who want to stand on principle and those who want to be more pragmatic," said Professor Tim Hagle, an expert in Republican politics at the University of Iowa.

The fight is also causing problems among other major Republican figures. New Jersey governor Chris Christie, seen as a leading contender to run for president in 2016, fumed that the "toxic internal politics" of the Republicans in the House had been partly responsible for failing to pass a bill that would deliver billions of dollars of vital aid to areas in the north-east hit last year by Hurricane Sandy.

The split also represents different ways of looking at where the party's focus should be. Boehner and the more pragmatic wing of the party see the Republicans' 2012 defeat as a sign that the party is losing touch with a younger and more ethnically diverse national electorate that can deliver a candidate to the White House. The party's conservatives, however, look to their own party's still Tea Party-infused base and gerrymandered congressional districts that too often provide safe seats to extremists.

As the 2014 mid-term elections hove into view, some observers believe that those backing Boehner could be punished for their 'yes' vote and further undermine Boehner's position. "Some of those Republicans who voted for this are going to lose their seats because of this one vote," said Mitchell.

That means Cantor's dissent could tie in with eventual ambitions to take Boehner's job. If Republicans in the House emerge from 2014 even more in the grip of conservative ideologues, he will be well-placed to launch a bid for the speakership himself. "Cantor is a shrewd political animal. He is incredibly ambitious. He will do whatever he needs to do to take control of that speaker's gavel," said Professor Cohen.

That would defy a general consensus view that says Republicans should not repeat the sort of presidential primary that marred the 2012 race, when the Republican field was dominated by misfit candidates who courted the rightwing base at the expense of wooing centrist Americans. Cantor's rise would see the party go even further right. It is a problem that Boehner is no doubt aware of.

"Boehner has a problem on his hands. He could only get a third of his party to vote for the fiscal cliff legislation. That is a sign of weakness," Cohen said.

guardian.co.uk © Guardian News and Media 2013