The VA take over by the left was planned coordinated multi pronged effort. It would have failed but the VA GOP is divided and so they won. The NoVa RINOS will not vote for a Tea Party type candidate, ever. So they stay home. Ask Cuccinelli. The national GOP "leadership" sees this division and so they stopped spending any money in VA. In a way the GOP is still mad at VA "rednecks" for kicking out their heir apparent Eric Cantor.
So the attack from the left was redistricting, large amounts of Soros money on local races and weak GOP leadership that just pretty much gave up. It was textbook dirty politics.
The only good news is the Democrats are now over playing their hand.
Very badly so and it has fired up the national base IMO