This may be the biggest upset of the 2010 election season: conservative media commentator Christine O'Donnell defeated centrist Congressman Mike Castle in the Delaware Republican Senate Primary.

O'Donnell led 53.2 - 46.8 percent with 98.5 precincts reporting, and media outlets have called the victory hers.

After intense scrutiny over the past few weeks, the result of this election, although it's one Senate primary in a small state, will resonate throughout the political world as a sign of the times--proof that conservatives and Tea Partiers really are a powerful bloc of voters in the present Republican electorate, and that the Tea Party movement in particular has succeeded in steering the party drastically to the right on its core issues.

How this will play in November is anybody's guess.

O'Donnell was not considered to be a serious contender for this seat a mere two weeks ago. Of the top Senate races in the country, the Delaware primary was rarely--and, possibly, in fact, never--mentioned by news outlets, party operatives, or political commentators as a competitive race to watch.

What changed things was one event: Tea Party Express endorsed O'Donnell on August 31, just having poured hundreds of thousands of dollars, taken from sub-$5,000 donations solicited through email requests--into Alaska and knocking off incumbent Sen. Lisa Murkowski, whom the Washington political world had also deemed completely safe. After O'Donnell gained some momentum with that group's backing, Sarah Palin and Sen. Jim DeMint endorsed her late last week. To be sure, the three TV ads run by Tea Party Express were the major difference in Delaware between August 31 and September 14. 

After what will come out to be just over $250,000 of Tea Party Express spending in Delaware, the movement will have claimed another state, adding to the primary victories of Joe Miller in Alaska, Sharron Angle in Nevada, Rand Paul in Kentucky, Ken Buck in Colorado, and Mike Lee in Utah. Other Tea Party candidates were fared well Tuesday night, as businessman Ron Johnson advanced in Wisconsin's Senate race and Reid Ribble emerged from that state's eighth-district House primary.*

This is the third large, consequential victory for Tea Party Express alone in 2010. Before Alaska, the group fueled Senate candidate Sharron Angle's meteoric rise over the GOP field in Nevada.

It's a sign that a national donor base of conservative activists has tremendous power over the Republican Party and national political dynamics in general these days. No Republican appears to be safe from the ire of the Tea Party.

What makes this so amazing is that O'Donnell won despite being, on paper, a deeply flawed candidate. She brought a laundry list of past financial issues with her into this race, most of which were already public in the Delaware media. Her 2008 campaign owed over $10,000 when she launched her 2010 campaign; she sold her house to her campaign lawyer in 2008, facing foreclosure; she didn't receive her bachelor's degree from Fairleigh Dickinson until earlier this summer, due to unpaid charges to the university.

These facts were made very public over the past few weeks, and most expected them to damage O'Donnell significantly, the idea being that she was running on a campaign platform of fiscal responsibility, and that her own financial troubles completely undermined it.

But they didn't damage her. She won out in the end. And now she'll face Democrat Chris Coons, who finds himself a much more competitive candidate as of this very moment: Coons trailed Castle significantly, 12 percentage points in polls, but he leads O'Donnell by 13.

The Tea Party wins. Maybe Democrats win, too. Regardless, all the theories put forth about how the Tea Party could change the 2010 elections seem to be coalescing into reality.

*This post was updated with these numbers.

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