I think we can predict that a lot of Democrats — especially those who want to argue that the Virginia results are not worrisome for the party in next year’s races — are going to say they’re a function of McAuliffe’s weakness as a candidate.
Cutting against that spin: McAuliffe is a former governor and the only candidate who has ever beaten the state’s trend of electing governors from the opposite party of the president (something he did in 2013, albeit narrowly). The more Democrats deny the race is a sign of things to come, the more it will be.
Update: Since I wrote this post, it has become clear that there was a large swing away from the Democrats in New Jersey, too, which further undermines the idea that their poor showing in Virginia was mostly a function of McAuliffe.