Turnout was high, not low. There are already 16% more ballots counted in Virginia than there were in 2013. And there are provisional and absentee ballots to count. Anyone who tries to spin that Ed Gillespie lost because he wasn't conservative enough or enough like Trump are barking up the wrong tree. He has 16% more votes than the 2013 nominee, conservative Ken Cuccinelli. Gillespie didn't lose because voters didn't turn out for him. he lost because Ralph Northam has 31% more votes than Terry McAuliffe got in 2013. (Note: If one candidate got 31% more and the other 16% you'd think turnout would be more than 16% higher. In 2013 3rd party candidates got 7.0% of the vote. Yesterday they got 1.2%.)
Gillespie did very well in getting right leaning voters to show up to the polls and vote for him. Northam just did a lot better. Democratic enthusiasm showing up at the polls is good news for Democrats but Gillespie doing much better than Cuccinelli is a silver lining for the GOP. There's going to be a drop off in voters from a Presidential election to any non-Presidential one. In 2013, McAuliffe got 54% of Barack Obama's 2012 vote total. Ken Cuccinelli got 56% of Mitt Romney's. This year Northam got 71% of Hillary Clinton's vote total, while Ed Gillespie got 66% of Donald Trump's. And, as I said, there are still ballots to count.
As elections this year have shown, Republicans haven't had a problem turning out their voters. They are actually turning out at higher than expected numbers. Their problem is that Democrats are doing even better than that. The worst combination for a party is when the other party is enthusiastic while your party isn't. There's not much you can do there. If your party is enthusiastic while the other party is more enthusiastic you can win if the other party is a little less enthusiastic. We don't have any reason to expect Democrats not to be as enthusiastic as they were last night but such high enthusiasm levels can be tough to maintain across the country. That doesn't mean Republicans will do better in 2018 than Democrats did in 2010 or 2014. It does mean they are more likely to do better than the Democrats were then.
Virginia Democrats did extremely well in traditionally Republican suburbs that have been getting bluer. The voters continued to support Republicans down ballot even as they voted for Hillary Clinton over Donald Trump. Republicans did very well in rural white working class areas.
From the New York Times:
Of the 16 districts where Democrats currently lead in Virginia, Mrs. Clinton won 15 of them and received 49.7 percent of the vote in the other, according to data from the Virginia Public Access Project and Daily Kos Elections.
If this continues it's extremely bad news for Republicans holding the upscale suburban districts that went Clinton but voted Republican down ballot again. There are 22 districts that voted for Hillary Clinton but voted Republican for congress. The good news for Republicans is that some more traditionally Democratic areas that went Trump in 2016 went for them last night. Congressional Democrats won 11 districts Trump won in 2016. Democrats need to pick up 24 seats to win the House of Representatives. They'll have to win most of the districts Clinton won and some Trump won. If they lose their own districts that Trump won in 2016 they'll have win even more Trump districts in 2018. As good as this election might be for Democrats all it shows is that they can win in areas Hillary Clinton won. Unfortunately for them, that won't be enough.
That shouldn't discourage Democrats. Right now they look better than they have at any time since 2008. Not taking the House next year would be a disappointment but they've only had a higher percentage of the House vote in one of the last four elections. If they only do good it's a lot better than they have been doing.