The establishment struck back.
Two weeks after House Majority Leader Eric Cantor's primary loss to a little-known and underfunded tea party challenger rocked the Republican Party, incumbent and mainstream GOP candidates came out on top in several high-profile primary showdowns.
In Tuesday's marquee race, longtime Sen. Thad Cochran of Mississippi narrowly fended off a fierce primary challenge from state Sen. Chris McDaniel, who edged Cochran in the primary three weeks ago. Cochran's victory might have come from crossover Democratic voters - courted by the senator - who cast ballots in the runoff.
Cochran was joined by Rep. James Lankford, who easily won the primary in Oklahoma over two other major candidates who enjoyed tea party support in the race to succeed a retiring senator. Former Rep. Bob Beauprez, considered the mainstream pick in Colorado's GOP gubernatorial primary, topped three other candidates. And former South Carolina Attorney General Henry McMaster, the ultimate insider, won a landslide victory in the state's Republican lieutenant governor runoff.
In another high-profile showdown, Democratic Rep. Charlie Rangel of New York, who was first elected to Congress 44 years ago, claimed victory in what he says will be his last campaign. But Rangel's opponent, state Sen. Adriano Espaillat, who nearly ousted Rangel in the Democratic primary two years ago, wasn't conceding the tight race early Wednesday morning.
And in Maryland, outgoing Gov. Martin O'Malley, a potential 2016 Democratic presidential contender, wasn't on the ballot but might have been the biggest winner of the night.
MORE on CNN.com
Six states held primaries on Tuesday, and once again anti-establishment candidates came up short in high-profile Republican showdowns.
That's a sharp difference with what we have seen over the last two election cycles, when establishment Republicans were overwhelmed by the insurgency in their own party and did little to stop it. But they appear to have turned the tables on the conservatives so far in this election cycle and have a string of victories to show for it.
Here are five things we learned Tuesday night:
1. Establishment GOP has learned to play ball: Since its birth in 2009, the tea party has had successes in primaries but those have given the GOP plenty of headaches and hurt its chances of winning back the Senate, effectively costing Republicans five winnable elections over the last two cycles.
This year, the establishment has had the upper hand in most contests against tea party-backed challengers. Showdowns on Tuesday in Kentucky, Idaho and Georgia kept that winning streak going.
In Kentucky, Senate Minority Leader Mitch McConnell easily dispatched Matt Bevin, who enjoyed the support of tea party activists and anti-establishment groups. It was a similar story in Idaho, where eight-term Rep. Mike Simpson also beat back a similar challenge from the right. And in Georgia's free-for-all Republican Senate primary, the two finishers who now move onto a July runoff were considered the most acceptable to the establishment.
How did they do it?
The winners all ran smart campaigns and were fortunate that the losers stumbled. And outside help also made a difference. The pro-business U.S. Chamber of Commerce spent more than $4 million to support McConnell, Simpson and Rep. Jack Kingston, who will face off with businessman David Perdue in the Georgia runoff.
One reason for the winning streak: The establishment has learned how to play ball with the tea party.
"Every establishment candidate ran like a tea party candidate. It's hard to tell the difference this time around, because they had a uniting factor in opposing Obamacare but also united on issues like immigration and trade and climate change. The establishment Republican Party ran to the right this time," said CNN Chief Political Analyst Gloria Borger.
While Democrats argue that the move to the right will backfire on the GOP come November, midterm elections are traditionally low turnout affairs compared to presidential elections. And in such contests, the key to victory is often getting out the base.
MORE on CNN.com