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Whatever the result of Tuesday's races, 2010 will be remembered as the year of the tea party. In part, that's because of thousands of Americans who, in a time of national crisis, decided to throw themselves into politics. The movement, barely 12 months old at the start of the year, became the most dynamic political force of 2010.

Tea party-backed candidates didn't win every race they entered during 2010—and undoubtedly won't prevail in every race Tuesday. But in a spring and summer of surprises, they did displace at least a half-dozen long-time incumbents.

More broadly, the movement re-energized—and in some cases, scared—conservatives demoralized and dispirited in the aftermath of the Bush presidency and Obama victory. It brought dozens of new politicians to the fore, and redefined the debate on issues including health care and spending in a way that put Democrats on the defensive.

In May, Sen. Mitch McConnell, the GOP's leader in the U.S. Senate, was campaigning for the opponent of tea-party candidate Rand Paul in the senate contest in his home state, aided by party stalwart Dick Cheney. Paul won anyway. By the fall, GOP House leaders were crafting a "pledge" that was specifically designed to capture the movement's mantle.

Some GOP leaders worried the tea-party wave could drown them as well; others smelled opportunity. Most tried to court it and reflect its will by painting themselves as a grass-roots uprising against big government.

Democrats pushed to define it as extremist—with limited success. Once the primaries ended, the tea party's energy helped refill the sails of hundreds of GOP candidates as activists and money streamed back into action from the political sidelines. A Wall Street Journal/NBC poll in October found that more than one-third of all likely voters described themselves as tea-party supporters.

By Election Day, the tea party was both the dominant force in conservative politics and a movement defined by distinct factions and hard questions. "Is the tea party going to become a third party? Is it going to replace the Republican party? I don't know. Those are huge questions," says Mike Power, 61, a gray-haired retired businessman who started a tea party group in Morgan County, Ala.

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