EDITORIAL: Democrats finally get some good electoral news

Off-year elections are rarely kind to the party holding the White House. And on Tuesday, Donald Trump and the Republicans received a preview of what they can expect next year if their internecine squabbles continue to obstruct their agenda.

Distraught Democrats have been in desperate need of electoral victories after blowing the presidency and failing to regain the Senate last year. A string of recent losses in special House elections that they turned into referendums on Mr. Trump only compounded their despair. But those setbacks are now largely forgotten after they easily won gubernatorial races this week in both New Jersey and Virginia. The victories give Democrats momentum heading into 2018 as they seek to regain control of Congress.

House Minority Leader Nancy Pelosi, who has presided over a stunning loss of Democratic seats in recent years, crowed that the “door is open” to retaking the lower chamber. Senate Minority Leader Chuck Schumer called the election results a “rejection” of Mr. Trump.

Perhaps. But it’s risky to draw sweeping conclusions, particularly in states that have recently been reliably blue. Fact is, a GOP victory in either race would have been an upset and foreshadowed difficulty for the Democrats.

The balloting, however, sends a clear message to Republicans: They can’t expect to maintain voter support or draw new backers if they fail to deliver on their campaign promises while holding the Oval Office and Congress. The Obamacare fiasco remains a massive blot on their record and only further emboldened critics who question their commitment to the principles they espouse on the hustings. Mr. Trump has done an admirable job of rolling back Obama-era regulations, but to date he lacks a significant legislative accomplishment.

All this makes it even more imperative that Republicans enact significant tax reform.

The GOP still has the advantage of a favorable electoral map next year, particularly in the Senate. Democrats must defend three-quarters of the 33 seats in play, and many of those are in states the president carried handily. Republicans have suffered a number of incumbent retirements in the House, but Democrats still need to flip 24 seats. In addition, Republicans hold a fundraising edge at this point.

A year is an eternity in politics, of course. Democrats have their own internal rifts, but motivation and unity shouldn’t be an issue for the anti-Trump crowd and the “resistance” come 2018. The most effective way to counter such energy is to prove to traditional GOP voters that the party can deliver on vital issues such as tax reform. Absent that, Republicans only enhance their chances of electoral defeat and again risk squandering their opportunity to move the nation forward.