The Tea Party already guaranteed that next year's US presidential election would be even noisier than usual, but now there is Occupy Wall Street to throw into an unpredictable mix.

US presidential elections can be formulaic, with the two candidates and their huge political machines rumbling over familiar battlegrounds, the advertising deluge, the debates, and the compulsory last-hour dashes through key states.

In 2012, though, President Barack Obama and his Republican challenger will also have to navigate an unusually high level of grass roots protests that neither can fully control.

The elder of the two movements is the Tea Party, which in the 2010 midterm elections showed it had graduated from political sideshow to powerful force in favor of fiscally conservative, often anti-immigration Republican candidates.

Then six weeks ago a new kid on the street materialized in the shape of Occupy Wall Street, a ragtag collection of protest camps that started in New York and spread to several cities nationwide and abroad, notably London.

Although they share frustration at the elite, the Tea Party and OWS differ starkly, with the former advocating libertarian or plain right-wing reforms and the latter a still poorly defined, left-wing "revolution."

Analysts predict a strong role for the Tea Party in mobilizing Republican passions, but the jury is still out on whether OWS will evolve into a Democratic counterbalance, or whether it will continue its current policy of trying to stay outside established politics.

Zephyr Teachout, professor of law at Fordham University, said "both movements gave a name to a previously undefined cluster of beliefs. Before Occupy Wall Street, there was no short-hand for leftist populist outrage."

However, Teachout said it was far from certain that OWS will emulate the Tea Party's entry into the mainstream political ring.

The Tea Party has become so inseparable from big, conservative-minded media organizations and prominent Republicans that critics talk of it taking the entire Republican Party hostage.

By contrast, OWS refuses even to state clear goals, let alone endorse candidates. That policy has come in for derision from some quarters, but Teachout said it was "one of the more fascinating strategic decisions."

"It allows it to exist, at least for now, as an unfinished sentence -- 'I want,' 'I need' -- into which people who are feeling powerless pour all kinds of wants and needs."

Its future, in part, "depends on what happens when politicians try to engage directly and claim the name for themselves," Teachout said. "So far I haven't heard of people running on the 'Occupy' ticket, but its certainly possible."

Scott Stanzel, a spokesman in the George W. Bush White House and now a Seattle-based consultant, said OWS would have little clout, compared to the Tea Party, in the election.

"I think candidates will have to address the frustrations that people feel. Things aren't going well in this country. For the last several years with unemployment over nine percent, people are likely to be frustrated and upset and angry at Washington," Stanzel said.

But while "both groups share frustrations with the current status of our country," the Tea Party is "in a much better position to broaden their support," he said.

"Occupy Wall Street protestors appeal to a very far left constituency that, yes, has influence in certain areas..., but in terms of making a difference in elections throughout the country in elections, I don't see that."

But Bill Dobbs, a spokesman for the OWS protest in New York, said the movement's strength and growing influence comes from staying as outsiders.

"Supporting candidates and parties will just deflate the pressure," he said. "We are not a political party, we are not engaging in elections we are a loud outcry hoping to galvanize people into taking action."

"The outcry here is about economic justice. That's a very large bundle of issues and there is going to be a lot of different approaches," he said.

"Just a few months ago those were not topics that got a lot of attention, because there is tremendous cynicism here.... Now there is another idea, which is how to take action and the hope that people learn how to organize and give that loud uproar."