First they were ignored. Then they were derided as the tools of Big Money. Then they were branded as racists, the unhinged, the unwashed, the paranoid, the subversive and the ignorant - or some combination thereof.
Now, they stand accused of aiding and abetting the enemy by splitting the Republican party and giving Democrats hope for the November mid-terms. It has been a rough ride for members of the Tea Party in the 19 months since their movement sprung up.
But each insult and attempt to marginalise them seems only to have stiffened their resolve and swelled their numbers. Polling indicates that they are now more popular than either Republicans or Democrats. Despite all the claims they are extremists, around half of the electorate now identifies with the Tea Party and up to a quarter view themselves as members.
The time for them to be taken seriously is long overdue. The Tea Party will be pivotal in November. It has ripped up the playbook for the 2012 Republican primaries. Asnd it could just end up kicking President Barack Obama out of the White House.
Christine O'Donnell's Senate primary victory in tiny Delaware last week rocked the world of the Republican establishment in Washington. Widely portrayed as a kook and bitterly opposed by the Republican party, she defeated Mike Castle, a moderate Republican who had held continuous political office in the state since 1965.
Castle was widely regarded as a shoo-in against the Democrat on November 2nd. O'Donnell is a political novice and a patchy campaigner. The secret of her win? Endorsements by Sarah Palin, the former Alaska governor, and the Tea Party.
Oh, and Delaware primary voters didn't give a fig about Castle's electability. As far as they were concerned, he was a professional politician who was a RINO - Republican In Name Only - who could not be trusted. In the Senate, he might switch parties or vote with the Democrats to give Obama a bipartisan sheen. And, after 45 years in office, why not give someone else a chance?
The Tea Party has often been portrayed as a fringe group within the Republican party or a support network for Palin.
Dig deep and you will find that it is neither. There is, of course, a problem with the word "it". Although the Tea Party is referred to as a single entity, it is really a loose conglomeration of some national organisation and a plethora of groups formed in local neighbourhoods all over America. Standing for Taxed Enough Already, it took its inspiration from the 1773 Boston Tea Party protest against British colonialists.
A desire for small government, lower taxes and fidelity to the United States Constitution binds members together. There is a prevailing mood of anger towards Washington and a sense of having been conned. Mention the $700 billion (£448 billion) bailout, health care reform or cap and trade legislation and they will go into conniptions.
But beyond that, the Tea Party is a vast, teeming muddle of opinion and impulses. Many of its strong supporters don't attend public meetings. "The Tea Party is more an attitude than anything organised," one Southern conservative told me.
I used to think that the highest expression of American democracy was the Iowa caucuses. There, on a freezing evening in Des Moines, Iowa in January 2008 I watched ordinary citizens trudge through the snow to pick their favourite Democratic presidential candidate.
Obama was their man and the caucuses were his launch pad for the White House. Checking back, I described the scene in the school gym as "grassroots politics at its most vibrant".
That was before I attended a Tea Party event. The gathering I chose was essentially at random. I happened to be in Cincinnati, Ohio and wanted to see a local event, rather than a big Tea Party rally, for myself. A few hours later, I was inside the Old Spaghetti Factory in Fairfield, Ohio.
Only a handful of the 100 or so people there knew I was a journalist. The event was a monthly meeting and open to the public. Quite a few had been among the 5,000 who gathered in Cincinnati's Fountain Square in March 2009 for the first Tea Party event in southern Ohio. For some, it was the first time they had showed up.
The discussion ranged from the philosophical, pondering the role of government and the duties of citizens, to the practical, how to canvass and organise. And while there was certainly anger about the state of the country and disdain for Obama there was also humour and good cheer. Anyone could take the microphone, and many did.
It was clear that the group saw itself as watchdog rather than a lap dog of the Republican party. Ed Pharo, a US Army veteran and father of five, lamented the high level of taxation in Ohio. "One party didn't do that," he said. "Two parties did that. One was complicit with the other."
The aim for the November election, he told the group, should be to "stop the bleeding" by defeating as many liberals and RINOs as possible. "Then we're going to watch these new people that we put into office and make sure they don't turn into knuckleheads like the old people."
There was no talk of race, apart from the need to broaden the base of the Tea Party (there was no black person in attendance) and to combat what Pharo described as "these ridiculous accusations of racism and the Klan".
No one questioned Obama's citizenship or his allegiance to the country. Fiscal matters predominated and social issues were barely touched on. There is no doubt that the Tea Party has attracted some eccentrics and extremists. But what popular movement hasn't?
Afterwards, Katy Kern, leader of a Tea Party group in nearby Liberty Township. Sporting tea pot earrings, she told me that "Republican royalty" did not realise how independent the movement was. "This is their last chance. If they get in and screw it up, we're bolting. They'll find that this dog won't hunt."
Adriana Inman, a co-leader of the Fairfield group, saw the Tea Party as an awakening. A mother and courts interpreter of Colombian parentage, she had never been involved in politics before. "We have been silent for too long, enjoying the American life and giving our kids what we can," she said.
The Republican primary system is such that ordinary people can reject the choice of the party hierarchy. This has now happened with Senate races in Florida, Alaska, Utah, Kentucky, Colorado and Nevada as well as Delaware.
For all the talk of how the Tea Party will help the Democrats by splitting the Republican vote, the first five of those states are highly likely to result in Republican/Tea Party wins, Nevada is in the balance and only Delaware looks like an uphill struggle. Increased conservative turnout and the energy generated by the Tea Party is likely to punish Democrats disproportionately.
The reaction to O'Donnell's win may yet lift her close to victory. No candidate since Palin has been ridiculed and lampooned as she has, mainly for Christian conservative views she expressed a decade or more ago. She has also been castigated for having been in debt and taking years to pay university bills.
This patronising condescension sits uneasily with ordinary Americans, one in seven of whom are now officially poor and most of whom have at one time or another struggled to pay the bills. Populism is a key strain in the Tea Party. Republican elites beware.
The biggest test of the Tea Party's power will come in 2012. It would be unwise to assume that Palin is the only one who stands to benefit. Some Tea Party groups are very pro-Palin but others are wary of her celebrity and her decision to quit as Alaska governor.
She perhaps didn't help herself in Iowa on Friday night when she suggested in a speech, ostensibly in honour of Ronald Reagan, that she might be "the one" for 2012 - the messianic term used by Oprah Winfrey when she endorsed Obama in 2008.
Some tea partiers fear that the type of cash Palin brings in could distort or even corrupt the movement. "As Tea Party types ascend, they are likely to be overwhelmed and compromised by the money and lavish surroundings that come with power," a Texas conservative warned me.
By this point in the 2008 election cycle, Obama had yet to emerge. Many Tea Party activists believe that a similarly fresh figure could emerge in 2012. The assumption that presidential campaigns were getting longer and longer is inoperative now that the Tea Party insurgency has taken root.
Senator Jim DeMint of South Carolina is loved by tea partiers almost as much as he is loathed by his party colleagues in the Senate. Representative Paul Ryan, only 40, is just the kind of fiscal hawk who appeals to tea partiers. At least another 10 Republicans are pondering a presidential run.
In 2008, the Republicans plumped for John McCain, an unreliable conservative who the party viewed as the next guy in line. This time around, the Republican nominee is more likely to be chosen by the people in the Old Spaghetti Factory than party leaders in mahogany-panelled rooms on Capitol Hill.
Establishment Republicans can change their ways and try to harness the power of the Tea Party or they can stand by for a hostile takeover. Democracy, they are finding out, is a messy thing.
Telegraph UK