Don’t get too cocky, Dems

For months the Virginia gubernatorial race has been seen as a bellwether of the Democratic Party’s capacity to rebound from its stunning loss to Republican Donald Trump in the 2016 presidential contest, and the results were about as good as Democrats could have hoped for. In what polls had suggested would be a neck-and-neck race, the Democratic nominee, Lt. Gov. Ralph Northam, trounced Republican Ed Gillespie by nine points, and Democrats picked up 14 seats in the state’s House of Delegates. And it wasn’t just in Old Dominion that Democrats dominated. They picked up New Jersey’s governorship, seats in Georgia’s legislature, and a senate seat in Washington state that gives them complete control of the governor’s mansions and legislatures up and down the West Coast. Maine voters overwhelmingly decided to expand Medicaid under the Affordable Care Act, and one of the leading social conservatives in the Virginia House lost to a political newcomer who happens to be a transgender woman.

Exit polls and turnout figures suggested an anti-Trump surge that more than overcame Democrats’ traditional weakness in off-year elections, and analysts are now suggesting the party may be the favorite to control the House of Representatives after next year’s midterm elections.

All we can say is, don’t get too cocky, Democrats.

The spate of wins for the party don’t erase the fissures that hobbled it in 2016 and have prevented it from unifying behind much of anything since except antipathy toward President Trump. Before Tuesday night, the big political story of the week for Democrats was the publication of former Democratic National Committee Interim Chairwoman Donna Brazile’s tell-all memoir detailing the combination of management dysfunction, missed opportunities and hubris that doomed Ms. Clinton’s candidacy last year. Ms. Brazile accuses the Clinton campaign of hijacking the party’s nominating process and forcing the DNC into a fund-raising strategy that effectively rigged the primary elections against the left-wing insurgency led by Vermont Sen. Bernie Sanders. Ms. Brazile was careful to say that nothing the Clinton campaign did was illegal. But it did drive a wide enough wedge through the coalition of middle class reformers, labor activists, minorities and young people assembled by the Obama campaigns to hand Mr. Trump a decisive victory in the Electoral College despite losing the popular vote on Election Day.

On Tuesday, Democrats won plenty of races based on voters enthusiasm to send an anti-Trump message. But the task in the midterms is much tougher. Democrats need to pick up three seats to control the U.S. Senate, but they are defending 25 of the 33 seats that will be up for election next year, and they would need to run the table and then some on the states that are expected to be competitive. Democrats have to pick up 24 seats to take the House, and despite polls showing a double-digit advantage for the party in a generic Congressional ballot test, incumbency and gerrymandering make that a heavy lift.

Off-year wave elections happen with some regularity, but it’s much more difficult to pull off without a clear agenda, and Democrats, still fighting the Hillary vs. Bernie primary, don’t have one other than opposing whatever Mr. Trump does or says.

Granted, the Republicans are at least as divided, if not more so, and their challenges were on full display Tuesday.

But as we head toward 2018, it’s clear that neither Republican ethnic nationalism nor Democratic identity politics can heal the divisions in American society or answer the problems we face in the 21st century. Anti-Trump fervor papered over that issue for Democrats on Tuesday, but that’s going to be harder in 2018 and might be impossible in 2020. We saw what happened last time when Mr. Trump went up against a fragmented Democratic party.

Tuesday’s elections showed that it’s possible for Democrats to bounce back from Mr. Trump’s election, not that it’s inevitable.