Republican beats back tea party challenger

The Republican establishment candidate in a key US Senate primary race handily defeated his tea party challenger, fueling the party's bid to defeat Democratic rivals in November elections.

In the biggest early crunch vote of the 2014 campaign calendar, North Carolina state House speaker Thom Tillis beat tea party-backed candidate Greg Bannon by 18 percentage points.

Tillis, who earned an endorsement from the party's 2012 presidential nominee Mitt Romney, will now face vulnerable first-term incumbent Democrat Kay Hagan in what is expected to be one of the costliest and most crucial races in the GOP's efforts to win the six net seats needed to take back the Senate.

"Congratulations to Thom Tillis on his primary win. Now, it's time to kick Senator Hagan out of office," Republican National Committee chairman Reince Priebus said in a tweet.

A handful of US states held their primaries Tuesday. Other establishment Republicans who won included House Speaker John Boehner, who was never under genuine threat in his race, and fellow Ohioan David Lynch, a first-term House Republican who faced a candidate supported by outside far-right groups.

But most eyes were on North Carolina, where incumbent Renee Elmers and 10-term congressman Walter Jones also defeated tea party-backed challengers.

Elmers likely faces Democrat Clay Aiken, the former American Idol singer who was narrowly leading in his primary, in the November election.

The Libertarian Bannon's defeat marks a blow for the tea party, the loose affiliation of low-tax, small government conservatives whose candidates won dozens of congressional seats in the historic 2010 mid-terms.

"While we obviously aren't happy with the outcome, we congratulate Speaker Tillis for his win," Tea Party Patriots co-founder Jenny Beth Martin said.

"The important thing now is to pick up a US Senate seat that's been in liberal hands for the last six years."

Senator Rand Paul, a prospective 2016 presidential contender who backed the tea party's Bannon, also said Republicans should now coalesce behind Tillis.

"It is time for our side to unite to defeat the Democrat who cast the deciding vote for Obamacare, Kay Hagan, in November."

The tea party faces another tough test later this month when its candidate squares off in the Kentucky primary against Mitch McConnell, the Senate's top Republican.