The Democratic wins in Virginia and New Jersey have buoyed the spirits of a party that had gained zero electoral success since Trump took office.  Four House races all went Republican despite favorable conditions for a Democratic takeover.

But Tuesday was a different story.  And the clear reason for Democratic success was their huge gains in the suburbs of major metropolitan areas.

College-educated, white-collar workers weren't going to give the GOP a majority of their votes anyway.  But the margin of victory for Democrats in the suburbs of northern Virginia and northern New Jersey among those voters was astonishing and should sound the alarm for Republican officeholders who represent suburban areas.

But as Ron Brownstein points out in The Atlantic, gaining a large majority of those voters, including women, minorities, and college-educated white-collar workers, would still bring them up short in 2018 of gaining a majority in the House.

But Democrats on Tuesday made much less progress cracking the competing Republican coalition, which revolves around older, blue-collar, non-urban, and evangelical whites who generally express anxiety about demographic, cultural, and economic change. Even amid Gillespie's lopsided defeat, he still held 72 percent of non-college-educated whites and nearly four in five white evangelical Christians. He also improved on the GOP's margins from 2013 in many rural southwestern counties. And 15 of the 16 state House seats that Democrats captured came in districts that Clinton carried, noted Geoffrey Skelley, the associate editor of the political publication Sabato's Crystal Ball.

A suburban recoil from Trump in places like New Jersey; the Philadelphia suburbs in Pennsylvania; and Orange County, California, can propel Democrats to the brink of a U.S. House majority: Eighteen of the 23 House Republicans holding seats that Clinton carried in 2016 represent districts with more white college graduates than the national average. And Republicans hold another 30 House seats with higher-than-average numbers of white college graduates where Clinton improved over Obama's showing in 2012. Tuesday's blowout is also likely to encourage more retirements among House Republicans in white-collar districts, increasing Democratic opportunity. Still, relying only on white-collar places would leave Democrats very little margin for error. Because the coalition of transformation is so centralized in the largest urban areas, it is better suited for winning the White House than either the House or the Senate (and even that advantage cracked with Trump's Electoral College win).

Tuesday's Democratic sweep illuminated the long-term threat the GOP has accepted by allowing Trump to define the party in a manner so toxic to the demographic groups and metropolitan population centers that are growing in the electorate. But Democrats will still be traveling a narrow path in 2018 if they can't regain more ground in Trump country than they did this week.

So if GOP candidates move closer to Trump, actually embracing him and his agenda, imitating his rhetoric, will that save their majority?

In fact, it's all Republicans have.  They can't repudiate Trump.  That would drive a significant percentage of their base away.  Nor will the Gillespie strategy of keeping Trump at arm's length while appropriating parts of his agenda work, either. 

Of course, they risk energizing this emerging Democratic suburban coalition even more, but it's a risk they are going to have to take.  One of the oldest adages in politics is "You dance with the one who brung you."  Trump paid for the orchestra and the dance hall, and now Republicans are going to have to dance with him.  Their ultimate hope is that their voters – older, white, non-college-educated, ex-urban, and rural voters – will go to the polls in greater numbers than they did on Tuesday night.