Washington (CNN) -- Establishment Republicans, backed by business-friendly outside groups, launched a counter-offensive this year against conservative Senate challengers after two election cycles of hard-right candidates winning GOP primaries but losing in November.
Republicans need to flip six seats this year to win back the majority and don't want the same scenario to play out again. The tea party's scorecard this year is far different than in 2010 and 2012, when it knocked off several establishment-backed candidates.
It's too early to say if the party's over, but as Stuart Rothenberg of the non-partisan Rothenberg Political Report wrote earlier this month, "it's already clear that the pragmatist conservatives have stopped the anti-establishment's electoral momentum."
• Firebrand Republican Rep. Steve Stockman launched a last-minute bid against Texas Sen. John Cornyn, but he never seriously challenged the incumbent. Cornyn won by more than 40 points.
• North Carolina state House Speaker Thom Tillis won big against his top two conservative opponents, winning enough of the vote in the primary to avoid a costly runoff that would have delayed his general election face-off against Democratic Sen. Kay Hagan, one of the nation's most vulnerable incumbents.
• The primary in solidly red Nebraska might have been the high-water mark for the tea party in this cycle. Ben Sasse, a former Bush administration official who was endorsed by high-profile conservatives like Ted Cruz and Sarah Palin as well as the Club for Growth and other well-funded conservative groups, beat his two primary opponents and will likely coast to victory in November.
• At the same time, no challenge emerged from the right against moderate Rep. Shelley Moore Capito in West Virginia, and she easily won the GOP primary there. Republicans hope to pick up the seat of retiring longtime Democratic Sen. Jay Rockefeller in November.
• After promising that the establishment would "crush" the tea party in 2014, Senate Majority Leader Mitch McConnell appears likely to do just that against challenger Matt Bevin. But McConnell faces a serious challenge from Democrat Alison Lundergan Grimes, who's already campaigning with Democratic stars and getting support from outside groups in what could be the most expensive Senate race ever.
• In Georgia, businessman David Perdue, Rep. Jack Kingston, and former state Secretary of State Karen Handel are the frontrunners, while two fiery conservative congressmen, Paul Broun and Phil Gingrey, trail in the race for retiring GOP Sen. Saxby Chambliss' seat. The winner of the GOP primary will likely face Michelle Nunn, the daughter of longtime Democratic Sen. Sam Nunn.
• In Oregon, Portland pediatric neurosurgeon Dr. Monica Wehby is the frontrunner over a more conservative state representative, Jason Conger, in the race for the GOP Senate nomination. The winner of that contest will face first-term Democratic Sen. Jeff Merkley, who Republicans think might be vulnerable if 2014 turns into a wave election for Republicans.
• Six-term Sen. Thad Cochran is facing a serious challenge from state lawmaker Chris McDaniel in Mississippi. Polling shows Cochran with a comfortable lead, but the establishment isn't taking the race for granted.
• Thanks to a pair of quirky TV ads, state Sen. Joni Ernst has surged ahead of a pack of Republican candidates vying for retiring Democratic Sen. Tom Harkin's seat in Iowa. Ernst is supported by the state's Republican establishment, but she also has support from Palin and other notable conservatives. If no candidate in the primary earns more than 35% of the vote, the nominee will be selected at a convention, which could favor a conservative. The GOP nominee will face off against Democrat Bruce Braley in the fall.
• In South Carolina, Sen. Lindsey Graham has long been vulnerable to a challenge on the right because of his calls for immigration reform, his support for President Barack Obama's Supreme Court nominees and his willingness to work with Democrats on some issues. But conservatives have not coalesced around any of his six primary challengers. If Graham is held under 50% in the primary, he will face off against the second-place finisher in a two-week runoff.
• Kansas Sen. Pat Roberts has faced questions about his residency and the amount of time he's spent in his home state, but he's still in the driver's seat in his primary against radiologist Milton Wolf.
• Tennessee conservatives have made noise about unseating longtime Sen. Lamar Alexander, lining up behind state Rep. Joe Carr. But Carr has failed to gain much traction statewide.