On a recent episode of NPR’s All Things Considered, three Democratic incumbents to the House—Cheri Bustos of Illinois, New York’s Hakeem Jeffries and David Cicilini of Rhode Island—were doing what Democrats do all too well: wringing their hands and overthinking a problem. The “problem” in this case: coming up with a single, unifying policy message for the midterm campaign despite the highly diverse slate of candidates. What message, they ponder aloud, could possibly work for office-seekers ranging from moderates to progressives to “democratic socialists”?

At this point, the interviewer asks the obvious question: Why not just make the midterms a referendum on Trump rather than a policy debate? A bad idea, we’re told. “To the extent that the president has lost support, that leaves room to have a dialog (about Trump), but it doesn’t mean the dialog should be anchored in bashing the president,” said Rep. Jefferies. Rep. Cicilini chimed in that Democrats need to focus on values and pocketbook issues over the issue of Trump. Otherwise, “even if we win, we’ll (only) be in the majority for two years.”

I have a solution to the Democrats’ messaging challenge, but first two historical facts that the NPR guests seem to have forgotten. First, statistics show that midterm elections are invariably a referendum on the party holding the White House; they’re not primarily about “pocketbook” or any other policy matters. The out-of-power party cannot circumvent this phenomenon; its only decision is whether to embrace it. During the Obama years, Republicans did just that, making those midterms all about Obama. The result was an energized base that gave Republicans steady, inexorable gains until they’d overtaken both the House and the Senate.

Which is the second historical fact that Democratic strategists seem to have forgotten when they fret over the consequences of staging a referendum on the president: the strategy works. It works especially well when the president has a low approval rating, and when the party in power’s specific policies are unpopular with a majority of the electorate. This is precisely the situation Democrats have inherited this year. Trump’s approval remains stuck at around 40 percent, and polls confirm that voters are adamantly against everything from killing DACA to trade wars to border walls to tax cuts for the rich.

Let’s review. Democrats would prefer not to make these midterms a referendum on the president, a strategy that has proven effective in the past and for which ideal conditions exist. Instead, they want to focus on somehow reconciling policy differences between the various wings of the party, a virtually impossible task that will only heighten public awareness of the party’s divided state.

Besides, there is no point in reconciling policies that can’t be enacted without congressional majorities and a Democratic president. Unlike Republicans, who championed repealing Obamacare with no thoughts as to how to replace it, Democrats have plenty of policy ideas. But reaching consensus about them can wait for a more propitious time; for now, bickering over policy is both premature and a pointless distraction from the real message voters need to hear this Fall, which is that Trump is dangerous, and Democrats need to be in position to serve as a backstop against his worst instinct.

Which leads to the excruciatingly obvious solution to the Democrats’ messaging problem. The most effective message Democrats could possibly deploy can be concisely stated in just two words: Stop Trump.

Vote Democrat to Stop Trump from erecting an expensive and pointless wall. Stop Trump from making America polluted again. (Remember, all key administration figures, like Cabinet Secretaries and the head of the EPA, must be approved by the Senate.) Stop Trump from giving the rich yet another tax break, as he is currently contemplating. Stop Trump from sabotaging the Affordable Care Act. Stop Trump from firing Mueller. Stop Trump from appointing any more conservative Supreme Court justices. Stop Trump from separating immigrant families.

A Stop Trump campaign would turn voters’ attention precisely where it needs to be right now—on the imperative to prevent Trump from doing further damage. Democratic leaders would do well not to belittle such a role, or to deem it somehow inadequate. For one thing, the damage Trump is doing—to our alliances, our world standing, our institutions and our less fortunate—is real. Stopping him is arguably the most noble service Democrats could perform. Certainly, it is the most urgent and important role a Democratic congress could play in a shared-power government.

A Stop Trump message has other advantages besides clear relevance. It’s a rallying cry with universal appeal to Democrats of every wing—plus a substantial number of independents. You can find an awful lot of Democrats who aren’t yet ready to abolish ICE or who wonder exactly how the country would pay for Medicare for all. But you’d be hard pressed to find a single Democrat who doesn’t support guarding against Trump’s personal and policy transgressions. The message also takes a page from the Republican messaging handbook—something the Democrats need to do more often—in that it is succinct, impactful and easy to remember.

Also, to borrow an advertising industry term, it’s a slogan that has “legs.” That means it can be built upon and used in many ways because there exists a whole arsenal of talking points to support it. Finally, Stop Trump represents a promise that Democrats can actually deliver on should they win Congress. Voters like that, too, as Trump himself has proved.

The time has come for Democrats to stop hand wringing and overthinking. Even if party leaders don’t recognize it, this election is not about Democrat solutions; it’s about minimizing White House-inflicted damage until 2020. The midterm messaging challenge, then, is one that’s easily solved. The only question is whether the party will embrace the solution in time.

Alan Taffel is president of Taffel Communications, a Virginia-based consultancy. He is the former Chief Marketing Officer of MCI and Worldcom.