Could the tea party shake up the U.S. Congressional elections in November?

That speculation is not entirely unfounded, since the loosely organized group, with its "taxed enough already" namesake and support of mostly conservative Republican candidates, has already seen more than a dozen of its favored candidates win in primary and special elections.

The group has had a recent string of victories in Republican primaries in Alaska, Colorado, Kentucky, New York and Utah, with Christine O'Donnell's victory over Rep. Michael N. Castle in Delaware being the biggest upset. But for all its attention in the press, how big -- or how little -- will tea party-backed candidates win in November? And will the movement eventually fizzle out?

Clay Ramsay, research director at the Program on International Policy Attitudes at the University of Maryland, said the tea party has already effected the November elections.

"They have already had a significant impact because they have been in primaries against established Republican figures and have unseated some of them -- and that is no small thing to do," he said.

Still, he forecast that one or two of the movement's favored candidates will win and one or two will lose. And weather the movement will help or hurt the GOP after the elections remains "ambiguous," he said.

John Fortier, fellow at the American Enterprise Institute, said: "For the most part, the tea parties will play an incredibly positive role for Republicans this election." He added that tea party Republicans will beat their Democratic opponents. "But there is a question about the future."

"In general, the tea party provides energy and turnout for Republicans," he said. "It is also a uniting force for Republicans, as their main focus is the economy and small government, which many Republicans and independents support even though they are not as intense about this issue as tea party members."

Polls show that many conservatives -- mostly Republicans but also some independents -- support the tea party's aims. And a substantial fraction of Americans -- between 30 percent and 50 percent in polls -- are relatively positive toward the movement, he said.

Darrell M. West, director of Governance Studies at the Brookings Institution, said voters agree with the group on the bad economy and that deficits are too high, but do not share the movement' s general ideological orientation. "Many of the tea party candidates are much more conservative than the country as a whole," he said. "This may help Democrats retain control of the Senate if voters conclude some of the Republican nominees are outside the national mainstream."

Dan Mahaffee, special assistant to the president at the Center for the Study of the Presidency and Congress, said that historically such populist trends have popped up amid times of economic difficulty and political deadlock.

The lifespan of the tea party will be determined by how long the economy takes to improve and how long the political system takes to start functioning again, he said.

But with economists predicting that the jobs picture will not return to pre-recession levels for years to come -- some even say a decade -- the tea party could be around for a while.

Despite their anger about the economy, some studies show that tea party sympathizers tend to be more economically secure than the rest of the population, Ramsay said.

He believes the bad economy, per se, is not the key driver of the movement. Rather, the sense of being deeply shaken up by the harsh economic downturn and the belief that the economic system in general is in crisis is what drives the movement.

"They seem to be the angriest people but they also seem to be the best off," he said.