WASHINGTON -- Senate Republican leader Mitch McConnell of Kentucky dispatched his tea party challenger with ease to win nomination to a new term Tuesday night, and nearly a dozen candidates vied for spots on the Georgia ballot for fall elections that will decide control of the U.S. Senate, highlights of primaries in six states.
McConnell, a five-term lawmaker and the embodiment of the GOP establishment, was pulling 60 percent of the vote. Challenger Matt Begin was gaining 36 percent.
Alison Lundergan Grimes, a prize Democratic recruit, won Kentucky's Democratic Senate primary with ease and was piling up 78 percent of the vote in a four-way race. She will challenge McConnell in the fall in a race expected to be among the costliest and most competitive in the country.
On the busiest night of the primary season so far, Democratic Sen. Mark Pryor of Arkansas and his Republican challenger, Rep. Tom Cotton, ran unopposed for their party nominations, pointing toward a highly anticipated battle in November as the GOP labors to gain a majority.
Pennsylvania Democrats eager to gain control of their statehouse sorted through four contenders vying to challenge Republican Gov. Tom Corbett, who faces an uphill battle for re-election in November. Idaho and Oregon also held primaries.
In Georgia, Michelle Nunn jumped ahead quickly as the first votes were counted in the race to pick a Democratic candidate for the Senate seat once held by her father, Sen. Sam Nunn.
Businessman David Perdue, Rep. Jack Kingston and former Secretary of State Karen Handel were among seven trying for the Republican nomination in a struggle likely headed for a two-way runoff on July 22. Reps. Phil Gingrey and Paul Broun also were on the ballot, and the presence of three incumbent lawmakers on the Senate ballot assured a large turnover in the state's House delegation come January.
Republican primary struggles between establishment-backed conservatives and tea party-favored rivals were a dominant feature in several states, as they had been earlier in North Carolina and will be later in Mississippi, Kansas and Alaska.
Some primary voters said they had made up their minds based on more than the names on the ballot.
"I'm conservative, but I think most of the tea party people are a little too extreme," said David Reynolds, 63, of Union, Kentucky, after voting in his state's Senate race. He said he cast his vote for McConnell over Bevin.
Republicans must gain six seats to win a Senate majority, and party leaders have made it a priority to avoid the presence of candidates on the ballot this fall who are seen as too conservative or unsteady -- or both -- to prevail in winnable races.
McConnell's drew a challenge from Bevin, backed by tea party groups in the state where they made their mark four years ago by sweeping GOP Sen. Rand Paul into office.
Out-maneuvered in 2010 when his preferred contender was defeated, McConnell responded this time by running ads featuring testimonials from Paul, and by hiring a top aide to Paul to run his own campaign.
For his part, Bevin stumbled through a campaign that included an appearance at a rally of cock-fighting supporters.
Plagued by low approval ratings, McConnell spent more than $9 million through the end of April on his primary campaign, according to Federal Election Commission figures. Bevin spent $3 million, and outside groups poured in $5 million more -- a three-way deluge of television advertisements likely to continue through the fall.
The Georgia Senate race was fiercely expensive -- $10 million had been spent on television commercials through the end of last week -- and highlighted the divisions within the Republican party. Perdue relied on his background as a businessman, while Broun and Gingrey ran farther to the right. Handel sought to capitalize on the backing of former Republican vice presidential candidate Sarah Palin, and Kingston had the support of the U.S. Chamber of Commerce.
In Oregon, Republicans picking a nominee to oppose Sen. Jeff Merkley chose between state Rep. Jason Conger and Monica Wehby, a physician.
There were gubernatorial primaries in Georgia, Oregon and Idaho as well as Pennsylvania and Arkansas, where the statewide primary marked the first broad test of a voter ID law that Republicans passed after winning control of the Legislature in 2012.
In Georgia, Republican Gov. Nathan Deal led two primary challengers in early returns. State Sen. Jason Carter, grandson of the 39th president, was unopposed for the Democratic nomination.
Both parties held gubernatorial primaries in Arkansas, where two-term Democratic Gov. Mike Beebe was barred from running.
Corbett's poor ratings in Pennsylvania drew a crowd in the Democratic gubernatorial primary. Among the contestants was businessman Tom Wolf, ho said he would spend $10 million of his own money on the race, as well as Rep. Allyson Schwartz.
A smattering of Republican House members faced primary foes, notably Rep. Mike Simpson of Idaho. Challenger Bryan Smith said the incumbent wasn't conservative enough, and drew early support from the Club for Growth in a bid to oust him.
Establishment groups rallied behind Simpson, and the Club for Growth quit running television ads for Smith weeks ago.
In Georgia, former Republican Rep. Bob Barr launched a comeback bid. Former Clinton administration official James Lee Witt ran unopposed in Arkansas for the Democratic nomination to the seat held by Cotton.
AP Writers Bill Barrow and Christina A. Cassidy in Atlanta and Adam Beam in Frankfort, Kentucky, contributed to this report.