CHARLOTTE, North Carolina (AP) — Republican congressional incumbents in three U.S. states fended off challenges from anti-establishment candidates, in the first of a spate of primaries testing the strength of the small-government tea party movement that first rocked the party years ago.

Tuesday's races marked the beginning of the political primary season in earnest ahead of the November elections, when control of the Senate will be at stake. Over the next several months, Republicans will hold numerous contests featuring incumbents or other establishment figures against tea party challengers.

The tea party movement has pulled the Republican farther to the right on issues such as immigration and taxes, energizing the conservative base in some regions of the country. But during the 2012 elections, tea party-backed candidates unseated establishment-backed Republicans in some primary races only to lose to Democratic challengers in the general election. The Democrats retained control of the Senate.

In one of the most watched primaries, North Carolina House Speaker Thom Tillis defeated tea party favorite Greg Bannon and Baptist Minister Mark Harris Tuesday for the right to challenge Democratic Sen. Kay Hagan in November.

Hagan, whom Republicans have made a top target in their drive to win a Senate majority in the fall, won her party's re-nomination over a pair of rivals with about 80 percent of the primary vote.

The Republicans, who are expected to retain control of the House of Representatives in November, are six seats away from a Senate majority and determined to put electable candidates on the ballot.

Tillis won the nomination by running as a proud conservative who's not terribly different from his tea party and Christian-right opponents. Now the question is whether he hewed so closely to his anti-establishment challengers that he will have trouble attracting moderate voters in a battleground state President Barack Obama won once and lost once.

Democrats now hope to paint Tillis as being too far right for the closely divided state. If they succeed, they not only might help their party keep its Senate majority this November; they also could prove that mainstream Republicans still haven't figured out how to harness tea party energy without getting scorched.

Republican incumbents were also prevailing in Ohio, another battleground state. Rep. John Boehner, the speaker of the House, easily defeated two tea party challengers as he seeks his 13th term in Congress. First-term Rep. David Joyce of Ohio had a slightly tougher time but was running well ahead of his tea party rival.

The Virginia-based Tea Party Leadership Fund spent some $320,000 in support of high school teacher J.D. Winteregg amid dissatisfaction among some Republic voters over Boehner's stances on immigration and the national debt. But Boehner never faced a major threat, heading into the final month of the campaign with some $3.3 million available.

In Indiana, Republican Rep. Susan Brooks easily fended off a challenge from the right, rolling up 75 percent of the votes in a three-way race.

Also in North Carolina, former "American Idol" runner-up Clay Aiken and textile entrepreneur Keith Crisco remained very close and without a clear winner in the Democratic primary for a seat in the U.S. House of Representatives.

Aiken's first political campaign drew an unusual amount of celebrity buzz thanks to his singing career and a second-place finish on "Celebrity Apprentice."

The winner of that primary will challenge incumbent Republican U.S. Rep. Renee Ellmers in November. Ellmers, first elected in the 2010 tea party wave, handily defeated her challenger in the heavily Republican district.

Aiken has said reporters are the only people asking whether being a gay man could impede his campaign to represent such a conservative district. Both he and Crisco touted themselves as centrists.

___

David Espo in Washington contributed to this report.