Cantor was defeated by Democrats voting in Virginia's open primary

[RandySF]

28. Already debunked even though I originally thought the same.

Virginia's lack of party registration makes it difficult to pin down whether Democrats crossed over in large numbers, but local level turnout provides some indirect clues on whether this phenomenon was widespread. On two counts, the data cast doubt on whether Democratic cross-over voting caused Cantor's loss.

While Republican primary turnout spiked by 28 percent over 2012, according to the State Board of Elections, Cantor received nearly 8,500 fewer votes this year than he did in the 2012 Republican primary, a drop that was larger than Brat's 7,200-vote margin of victory. Regardless of how many Democrats turned out to oppose Cantor, he still would have prevailed had he maintained the same level of support as in his 2012 landslide.

If Democrats showed up in large numbers to vote against Cantor, turnout should have spiked highest from 2012 in Democratic-leaning areas, with Cantor seeing an especially large drop-off in support. In fact, turnout rose slightly more in counties that voted more heavily for Mitt Romney in the 2012 presidential election.

Likewise, Cantor saw the biggest drop-off in support in Republican strongholds of Hanover (-44 percentage points) and New Kent (-44 points), counties where Obama drew just over 30 percent of the vote in 2012. In Henrico County where Obama won 55 percent support, Cantor's drop-off was a smaller 32 points. The overall correlation between Obama's county support and Cantor's drop-off was clearly negative at -.60, indicating that the higher Obama's 2012 support, the lower Republican primary turnout rose this year. This is consistent with the idea that Republicans largely drove the rise in turnout.

http://www.washingtonpost.com/blogs/the-fix/wp/2014/06/11/did-democratic-votes-doom-eric-cantor/