Rupert Cornwell: Trouble brewing as millions join the Tea Party protest

What is the most popular political grouping in America right now? It's not the Democrats, who've long since come down from the Obama inauguration high of just 12 months ago. It's not the Republicans, for all their hopes of big gains in this November's mid-term elections. No, according to one respected poll, it's a ramshackle, hot-blooded, iconoclastic and thoroughly conservative movement called the Tea Party.

The inspiration is ancient: that fabled popular uprising against remote and tyrannical government that took place in Boston harbour in December 1773. But the history of the modern Tea Party is even shorter than the reign of King Barack. Its birth is generally dated to 19 February, 2009, when an excitable market commentator for the CNBC business news cable network railed in a live broadcast from the floor of the Chicago Mercantile Exchange against the government's plan to bail out mortgage owners in over their heads.

The scheme, said Rick Santelli, simply "promoted bad behaviour" by "losers." Far better, he went on amid loud cheers from traders, to "reward people who carry the water, instead of drink the water... are you listening, President Obama?" If not, Santelli warned, "we're thinking of having a Chicago Tea Party". That was 11 months ago and basically, the tea party people have been at it ever since.

They are, of course, detested and mocked by America's right-minded media and intellectual establishment. For Democrats, they make perfect targets, depicted as mindless Neanderthals egged on by ranting right wing talk radio and TV hosts, deafened to the real world by the conservative echo chamber they inhabit. The Republican leadership meanwhile looks on them with a mixture of condescension and trepidation. As well it might.

Predictably, criticism from the élites has only fired up this pitchfork army of the neglected middle class. Where Obama is cool and analytical, Tea Party-ers are noisy and emotional. Most important there are millions of them, though the lack of a formal party structure makes it hard to estimate their numbers with precision.

But an NBC/Wall Street Journal survey in December found that while only 28 per cent of voters had a positive view of Republicans, and 35 per cent of Democrats, fully 41 per cent looked kindly on the Tea Party movement. Its policies are less platforms than visceral howls of opposition: to immigration, to deficits, to excessive taxation and excessive government, and, loudest of all right now, to the health care reform bill that the Democratic Congress looks set to send President Obama for signature in a few weeks.

And next month sees the first Tea Party national convention, featuring as keynote speaker – who else? – Sarah Palin. Tellingly, the lady has chosen to pass on CPAC, the traditional national gathering of conservatives held in Washington each February, to attend the inaugural Tea Party gathering in Nashville.

What happens thereafter is perhaps today's most intriguing single question in American politics. In the short term, the Tea Party could mean big trouble for Republicans just as they were licking their lips at the prospect of big gains on Capitol Hill – an expectation only heightened further by the announcement by two prominent Democratic Senators last week that they would not seek re-election.

Now though, the party faces new internal divisions that could be fatal. In a special Congressional election two months ago, right wingers – Tea Party men in all but name – forced out the official Republican candidate, splitting the party and handing Democrats a seat they had not won since the Civil War. Much the same seems to be happening in Florida, where Tea Party opposition may have doomed the state's popular Republican governor Charlie Crist, a moderate, in his quest for an eminently winnable Senate seat. Now activists darkly mutter about giving the same treatment to Republican candidates in other states who stray from the true path.

Historically, of course, third parties do not fare well in the US. Teddy Roosevelt took that route in 1912 and lost. In 1948, the white supremacist "States Rights" party could not break out of the Deep South. The Reform Party of Texas billionaire Ross Perot, who railed against deficits and "business as usual" in Washington, fizzled after 1992, while eight years later Ralph Nader and the Green Party were spoilers (but as Al Gore will attest, boy did they spoil.)

But then again, the Tea Party is a movement, not a party. The fact that it doesn't have a leader probably enhances its popularity. In so unstructured a movement, everybody can find something to their liking. Quite possibly, it will become the right-wing equivalent of MoveOn.org, the liberal ginger group that was born of protest against the Clinton impeachment in 1998.

However, another lesson of history is that a struggling economy, a broad discontent with the established parties and a pervasive sense of national decline can be a noxious combination for existing, discredited political orders. It's worth remembering that back in 1992, with the Cold War won and Saddam Hussein routed in the first Iraq war, with China barely a blip on the economic horizon – in short, when the US was in far better shape than now – Perot still secured almost a fifth of the popular vote. If some charismatic leader emerges from these swirling tea leaves, if the economy tips back into double dip recession, who knows?

Every sign is this winter of discontent will last a while yet. The polls may overstate the Tea Party's popularity, but the malaise and frustration that fuels the movement will not soon go away. One way or another, next month in Nashville could be fun.