Cantor couldn't survive in the jungle
I have no way of knowing whether this is just CYA nonsense, but Eric Cantor's polling outfit has re-polled the district and came up with some interesting analysis. According to these latest numbers, their mistake was in not realizing that this election was a sort of jungle primary where people of both parties and independents were all voting in the race between Cantor and Brat. It turns out that a majority of the actual Republicans who usually vote in Republican primaries voted for Cantor. And that explains why the polling was so off -- they only polled the normal primary voters. This race brought in a bunch of new voters, some Republicans, a bunch of Independents and quite a few Democrats who had no corresponding primary in which to vote:
The organic turnout of non-Republican voting Independents and Democrats clearly decided the race for Brat. Since they were not included in any past Republican primary voting samples, that is why our poll was wrong. In retrospect we needed to see this possibility and poll this race as if it were a special election and not just a typical Republican primary. The polling that we and others did from samples of past Republican primary voters was woefully inadequate in this case of an open primary for a national figure with no simultaneous primary on the other side. While the Republican primaries that we have polled for successfully this year so far have been served well by polling past Republican primary voters, this race needed to be polled from a general election voter sample that could account for our influx of new voters into the open primary.
You can't really say that it was specifically these voters who made the difference of course. Cantor didn't get 100% of the normal GOP primary voters either so who's to say which specific votes were the decisive ones. But it's interesting that it never occurred to them that there might be a few thousand people in the district who, having no other primary available, might just decide that they wanted to vote out a loathed national politician like Eric Cantor. It's exactly the sort of thing that happens when you become a poster boy for a scorched earth approach to partisan politics. You're safe in your little GOP bubble but the minute there's a little opening, there are going to be few people who will infiltrate and blow your little bubble sky high.
Look for Republicans to start shutting down the open primaries in the future. As long as they behave like political terrorists this could be a problem.