Enter stage right: now Ron Paul takes the lead

As Romney falters, the latest frontrunner in the Republican nomination saga is the most extreme

The race for the Republican presidential nomination has lurched into the final week before primary season with yet another unlikely challenge to longstanding front-runner Mitt Romney's presumed mantle of favouritism.

Ron Paul, the libertarian congressman from Texas, found himself catapulted into a lead of between two and five per cent in polls of Iowa, where GOP supporters will on Tuesday become the first in the nation to select their preferred candidate for the White House.

His sudden rise follows a now-familiar pattern in a contest which has so far been defined by fruitless attempts to find a credible challenger to the safe but perhaps unexciting Mr Romney. First came an unexpected surge; then a brief period of buoyancy; after that, a concerted backlash.

Mr Paul has for years ploughed a consistent furrow on the rightwards extreme of Republican politics. Among other things, he supports abolishing the Federal Reserve, returning to the gold standard, legalising drugs, and revoking the Civil Rights Act. His foreign policy revolves around principled isolationism, bringing almost all US troops home from overseas. If elected, he has promised to reduce government expenditure by a third.

Those views may not produce much traction among mainstream voters, but they speak to a demographic which is particularly vociferous in conservative and mostly rural states such as Iowa, where January 3rd's caucuses will herald the official start of primary season.

As a result, Mr Paul's stock has steadily risen in recent weeks, helped by the implosion of other candidates. Michele Bachmann and Rick Perry now poll at around ten percent. And Newt Gingrich, who only last month had a double-digit lead, is now at between ten and fifteen percent. Although this remains a peculiarly unpredictable race, Paul was yesterday hovering around 25 percent in polls of Iowa, with Mr Romney just behind him. In 2008, by contrast, he finished caucus night in fifth position, with roughly ten percent of the votes. Front-runner status brings its own problems, though. Yesterday, his foreign policy credentials were vehemently attacked by almost every other major candidate.

Mr Romney, for example, argued that Mr Paul's hands-off attitude towards Iran threatened US security. "The greatest threat that Israel faces, and frankly the greatest threat that the world faces, is a nuclear Iran," he said. "Actually one of the people running for president thinks it's OK for Iran to have a nuclear weapon. I don't."

Newt Gingrich suggested that he would rather vote for Barack Obama to receive a second term than elevate Mr Paul to the White House. "I think [his] views are totally outside the mainstream of virtually every decent American," he declared.