It doesn't sound like anyone saw this upset coming. Via TPM: Eric Cantor Loses To Tea Party Primary Challenger:

House Majority Leader Eric Cantor's (R-VA) lost to tea party primary challenger David Brat in the Republican primary on Tuesday.

The race was called at about 8:05 p.m. Cantor lost to primary challenger David Brat.

Who is Brat? He is an economics professor at Randolph-Macon College. Brat was regarded as a long shot candidate but Cantor's campaign still spent over $1 million on advertising to stress that the top House Republican is a "strong conservative."

Cantor's campaign also sent out mailers arguing that he's largely responsible for blocking immigration reform, signs, perhaps, that Brat seemed like more of a threat than he appeared publicly.

UPDATE: Here's more from The Hill: Cantor out in Tea Party shocker:

House Majority Leader Eric Cantor (R-Va.), the Speaker-in-waiting who was bidding for his seventh term in Congress, was defeated in a primary election by a little-known conservative economics professor, David Brat, in one of the most stunning upsets in modern political history.

Brat defeated Cantor despite having no experience in elected office and despite Cantor outspending him by a margin of nearly 20-to-1. The Associated Press called the race for Brat shortly after 8 p.m., an hour after polls closed in Virginia's 7th district. Brat was leading Cantor, 56 percent to 44 percent, with 80 percent precincts reporting.

For Cantor, the loss marks an abrupt end to a fast rise through the House leadership, a path that many expected would make him the first Jewish Speaker in U.S. history.

And it is perhaps the most significant jolt to the Republican establishment since the emergence of the Tea Party in 2009. While conservative activists have ousted veteran Republicans like Sens. Bob Bennett (Utah) and Richard Lugar (Ind.), a sitting majority leader has never been defeated in a primary election.

As recently as Friday, Cantor and his team in Virginia projected confidence.

“I’m just not worried,” Cantor’s Richmond-based political adviser, Ray Allen, told The Hill. Cantor's own polling showed him with a comfortable lead.

Brat told The Hill he was “peaking at exactly the right time.”

And indeed he was.

But there were warning signs for Republicans. Tea Party activists recently ousted a close Cantor ally as 7th district committee chairman. Brat ran hard against immigration reform, and the issue dominated conservative talk radio in recent days as the Obama administration's request of funds to cope with an influx of recently detained young illegal immigrants from Central America.

Cantor sought to neutralize the issue, running hard negative television attacking Brat as a "liberal professor" and sending direct mail pieces saying he fought President Obama on "amnesty."

"Barack Obama and Harry Reid: Pushing amnesty to give illegal aliens a free ride. Conservative Republican Eric Cantor is stopping this liberal plan," said one mailer.

In the end, Cantor’s defeat may doom immigration reform for years to come. Read on...

Digby has more on who we might have to thank for Brat's victory: Limbaugh was credited with winning the 1994 election. Meet the new Rush Limbaugh.

And here's more from Daily Kos:

In one of the most shocking primary upsets of all time, House Majority Leader Eric Cantor, the second-ranking Republican in the House, has lost to economics professor Dave Brat, a political unknown who was outspent 40-to-1. Cantor ran multiple attack ads against Brat, but Brat successfully made his outright hostility to immigration reform the centerpiece of the campaign, accusing Cantor of supporting "amnesty" and putting him on the defensive. [...]

So what happens next? Virginia law appears to forbid Cantor from pursuing an independent bid, though a write-in campaign seems possible. That would be an incredibly humiliating second act, though, and it's the one move that could throw this seat to the Democrats. Virginia's 7th District voted 57-42 for Mitt Romney, so without Cantor, Brat will be heavily favored against Democrat Jack Trammel, who, like Brat, is a professor at Randolph-Macon College.

Beyond that, Cantor's loss will reverberate throughout his party. Republicans had already deep-sixed any immigration legislation; now, they'll blast it into outer space and compete Hunger Games-style to see who can be the most anti-immigrant loudmouth of them all. Tea partiers everywhere will also crow, and undoubtedly the Beltway press will write tons of stories about their resurgence.

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