Apparently Cantor's defeat not due to the Tea Party: Heavy Democrat voting in Republican Primary

From The Hill newspaper:

"We had probably 15,000 card-carrying Democrats come into this primary. There's just no way to anticipate something like that," Allen tells The Hill. . . ."My guess is now looking at the precinct-by-precinct analysis, probably half this electorate wasn't Republican," he said. "There's not a pollster in this country who polls voters from the other party in primary."
His analysis mirrors McLaughlin's.
"Where the voter surge was, it was Democrats who united against Cantor, who don't like him. And the mistake for our campaign above all the others, we should have polled Democratic primary voters and see if they were going to come into the Republican primary," McLaughlin said. "That's really the difference here. The reason the poll was wrong is no one anticipated Democrats were going to come in and play and they did, and that was the surge in turnout. That's why the poll was wrong, we were polling off the Republican sample." . . .