Eric Cantor just lost.

The defeat of the second-ranking Republican in the House by an ill-funded, little-known tea party-backed candidate ranks as the biggest congressional upset in modern memory and will immediately generate a series of political and policy-related shock waves in Washington and the Richmond-area 7th District.

"People don't know how to respond because it's never been contemplated," said one Virginia Republican strategist, granted anonymity to speak candidly about Cantor's loss. (Worth noting: Cantor didn't just lose. He got walloped; David Brat, his challenger, won 56 percent to 44 percent.)

In conversations with a handful of GOP operatives in the aftermath of Cantor's loss -- a loss blamed largely on an inept campaign consulting team that misread the level of vitriol directed at the candidate due to his place in Republican leadership and the perception he supported so-called "amnesty" for illegal immigrants -- there were several common threads about what it means for politics inside and outside the House.

1. Immigration reform is dead. I'm not sure it was ever really alive in the House -- we've written plenty about how the average House Republican has zero incentive to support any immigration reform -- but Cantor's loss ensures that even chatter about making minor changes will disappear. Anytime an incumbent loses -- and particularly a well-funded incumbent like Cantor -- there are lots of reasons for the defeat, but this one will be cast as a rebuke of any moderation on immigration. Brat savaged Cantor as "100 percent all-in" on amnesty and accused him of "bobbing and weaving" on the issue. Any Republican member of Congress who was even contemplating going a step or two out on a political limb to vote for some elements of immigration reform will stop thinking that way immediately. Not only is immigration reform a no-go for Republicans in this election, but it may well be off the table -- assuming Republicans control the House -- for the next several years.

2. House legislative activity will cease. Again, there wasn't a heck of a lot of grand legislative plans before Cantor's loss. But that trickle will totally dry up now as Republican members avoid doing anything -- literally, anything -- that could be used against them in the many primaries still to come this summer and fall. Members will be afraid of their own shadows.

3. The "establishment strikes back" storyline will disappear. In the space of the last week, the narrative that the establishment has finally figured out how to beat the tea party has exploded. First, Mississippi state Sen. Chris McDaniel finished ahead of Sen. Thad Cochran in the state's GOP primary. Now, the Cantor loss. (And, on June 24, Cochran remains an underdog to McDaniel in the Magnolia State runoff.) A former Senate Appropriations Committee chairman and the second-ranking Republican in the House both (potentially) losing in less than a month means that the primary victories of Sens. John Cornyn (R-Tex.) and Mitch McConnell (R-Ky.) over tea party-backed opponents earlier this year will be forgotten -- or, at the very least, overshadowed.

4. Tea party challenges will surge. David Brat -- and McDaniel if he wins -- will become the newest tea party heroes, taking their places alongside the likes of Sens. Ted Cruz (Tex.) and Mike Lee (Utah). In the near term, that will embolden tea partyers who seemed dead in the water in their own attempts to take out incumbents. "What we have seen tonight in Virginia shows that no race should be taken for granted and all the money and position in the world doesn't resonate with an electorate that is fed up with a Washington establishment that has abandoned conservative principles," said Joe Carr, a conservative trying to knock off Sen. Lamar Alexander (R) in Tennessee. (To be clear: Attempting to ride the Brat coattails with a press release is one thing. Beating an incumbent like Alexander is something totally different.) In the longer term, there's every reason to believe that other prominent members of the GOP leadership -- in the House and Senate -- will face tea party challenges come 2016.

5. The race to replace John Boehner as speaker is now wide open. We've written before about how difficult it will be for Boehner to hold on to his speakership -- assuming Republicans keep the majority this fall. But now the heir apparent has been dragged under by a conservative uprising. The third man in command -- House Majority Whip Kevin McCarthy (Calif.) -- is not exactly a tea party darling or, stylistically speaking, the sort of hard-liner that the most conservative wing in the House likes. Add it all up and you are looking at what could be an absolutely bananas race to lead the House Republican majority come 2015.

Cantor's defeat will continue to send rumbles through the political system for the next few days -- and even weeks and months. Out-of-nowhere upsets -- particularly of such a high-ranking pol -- have a tendency to do that. What an amazing night.

Read more:

Eric Cantor and the biggest upsets in political history

Cantor's loss throws Congress into disarray

Did Democratic votes doom Cantor?

David Brat just beat Eric Cantor. Who is he?