GOP Rep. Charlie Dent of Pennsylvania announced this month that he was resigning from Congress and told Republicans: “Big wave coming—get off the beach.”

Dent is probably right. A little more than six months before the midterms, predictive models point to Democrats winning control of the House of Representatives. A strong history of pick-ups by the party out of the White House, disgust with President Trump, good results in special elections, 46 Republican retirements (compared to 20 Democrats), and an energized Democratic base all augur well.

The question isn’t whether the odds favor flipping the House, but whether Democrats should bank on it. And the answer—for anyone who cares about protecting American democracy—is an obvious no.

Six months is a lifetime in politics. Trump’s popularity won’t recover by fall, but a deal with North Korea and a couple of other breaks could shift the momentum just enough to protect vulnerable Republican seats. And the recent history of midterms strongly favors Republicans, who took the House in 2010. In 2014, turnout fell to 37 percent, the lowest in 70 years, with the steepest falloff among Democrats.

Most Democrats get it; they’re focused and girded for battle, with a bumper crop of young and exciting candidates, including a record number of women. But too many others wring their hands watching cable news without educating themselves about which seats in their states are in play and what they can do to flip them. And a remnant of lefties are still living in Jill Steinland—acting as if the midterms are in the bag and they can indulge in expensive primary fights over minor policy differences that drain resources from the constitutionally critical task at hand.

Are Democrats in danger of once again forming a circular firing squad? The Democratic Congressional Campaign Committee (DCCC) is so worried that it’s pressuring weaker candidates in some districts to drop out in favor of well-funded moderates with a better chance of winning in November. California, where a half dozen seats are flippable (one quarter of those needed to gain control), is a particular concern because the state’s “top two” primary system means a large field of Democrats could split the vote and leave two Republicans running against each other in the general election.

Liberal activists say pressure from the DCCC and other Washington types is exactly what they dislike about the Democratic establishment. It’s the same thinking, they claim, that forced the party to nominate Hillary Clinton over Bernie Sanders. Their message: Don’t ram moderates down our throats!

The problem with this argument is that it ignores the mechanics of actually winning elections, which require party discipline and rejection of the narcissism of small differences. Nominating the most liberal Democratic candidate in a Republican district may feel principled but it reeks of moral vanity.

Democrats with their heads screwed on right are reviving an old ethic: party and country over personal preference. In swing districts, that means often resisting the natural inclination to support the candidate they like best in favor of the one who can win in November. In Trump’s America, pragmatism is a moral imperative.

Litmus tests—on support for a single payer health care system or even gun safety—are unaffordable luxuries in this year’s primaries. In 1980, Ronald Reagan issued his famous 11th Commandment—“Thou Shalt Not Speak Ill of Another Republican.” With the GOP violating that dictum every day, we’ll see if Democrats pick it up and play as a team for a change. The DNC might consider asking each primary candidate to sign a pledge committing to campaign for the winner.

Lest we forget: The stakes are the highest of any midterm election in memory. Imagine if House Republicans sustain heavy losses but hang onto their majority (24 seats as of now) by a few seats. This confounding of baked-in expectations would depress millions and have profound consequences for American life.

At a minimum, it would mean: The end of any investigation of Trump, whose presidency would be immediately normalized, with all that implies for his I-told-you-so behavior; new life for a right-wing legislative agenda that would include slashing social spending and, quite likely, finishing off Obamacare; even less oversight of federal agencies emboldened to wreak havoc.

Now imagine if Democrats, in the face of gerrymandered districts and financial disadvantages, re-take the House. It then wouldn’t matter nearly as much if Trump fired Robert Mueller, Rod Rosenstein, and the rest of the Department of Justice. The Democratic-controlled House Judiciary Committee could hire a large staff to pick up where Mueller left off and use its subpoena power to complete the probe.

Even if a Democratic House didn’t vote articles of impeachment (and it probably would), we might finally get to the bottom of Russian intrusion in American elections and Trump’s myriad other assaults on the rule of law. When they speak privately, a surprising number of Republicans agree that their party needs a whipping this year so the process of small-d democratic and small r-republican renewal can begin.

Accountability can’t wait. Imagine EPA Administrator Scott Pruitt having to answer for his corruption and vanity on Capitol Hill. He literally wouldn’t have time to redesign his seal, much less trash the environment.

Then multiply the idea of true congressional oversight across the federal government. The lame questions aging senators asked Facebook CEO Mark Zuckerberg have obscured just how potent an energized majority can be when it wants to tie up a dangerous president in knots.

All the country needs is one house of Congress under the control of Democrats to remove or reduce the threat Trump poses in every area except foreign policy. Even there, a Democratic House would find ways to check his power, summoning national security adviser John Bolton to answer for any warmongering.

This new world of accountability depends, of course, on money. Well-funded special-election victories for Democrats are misleading; it’s much harder to crowd-source across dozens of districts. Despite slightly more contributions for competitive races, Democrats still trail overall.

So far, the Republican Party has raised about $262 million and the Democrats about $206 million for 2018. Some of the Republican haul comes from the $400 million pledged in January by the political network controlled by the Koch brothers, which is aimed at maintaining the party’s control of Congress and the state legislatures that will draw the all-important legislative maps after the 2020 census.

Most of that $400 million won’t be donated and spent until the fall, when Democratic challengers now touted as likely winners could find themselves buried under mountains of cash. And we don’t know yet how much more might be coming from other Republican billionaires, for whom $10 or $20 million to GOP candidates in October is like a bar bill. The Mercer family has been sidelined by the Cambridge Analytica scandal but is still expected to kick in tens of millions.

Money isn’t everything. To drive turnout, Democrats need a strong “kitchen table” economic agenda and bold ideas that move beyond identity politics. (Marijuana legalization, for instance, turns more young people on than old people off.) But the record conclusively shows you also need the Benjamins: The best-funded candidates almost always win in state and local races.

That’s why squandering money and grassroots organizing in divisive primaries or contests far removed from competitive House seats is so aggravating. Every dollar that goes to those races is one less dollar for democracy’s main event in the fall.

In New York, supporters of actress Cynthia Nixon, who is challenging New York Gov. Andrew Cuomo in the Sept. 13 Democratic primary, argue that even if she doesn’t win, at least she’s pushing Cuomo to the left. But it’s false for Nixon to charge that Cuomo, for all his faults, is “governing like a Republican.” No Republicans favor banning fracking, family and medical leave, and a big hike in the minimum wage, as Cuomo does.

Most unions get this. Despite her Trump-like handicap (being a celebrity who has never held public office), Nixon last week received the endorsement and a line on the November ballot from the Working Families Party. This caused the two major unions that have long supported that progressive third party—the Service Employees International Union and the Communications Workers of America—to pull out of the WFP. They recognize that intra-party ideological struggle would be fine in almost any election but this one.

After all, the New York-New Jersey region boasts at least a half dozen flippable House races. Many ostensibly “woke” New York Democrats are still asleep when it comes to Job One; they often can’t even name the vulnerable incumbent Republicans just a few miles away.

If they wake up and research nearby districts, they may find that Nixon’s Not the One—that the one who will help rescue the country from Trump is a moderate military veteran or businessman who might not be their dream Democratic candidate but will do just fine in these circumstances.

This same dynamic is at play across the country. In Ohio, former Rep. Dennis Kucinich is challenging Richard Cordray, former director of the Consumer Financial Protection Bureau, in the Democratic gubernatorial primary. It’s not just that Cordray is a fine public servant and Kucinich a leftwing gadfly who has played footsie with Trump and would likely lose to the Republican in November. The real reason Dennis is a menace is that he’s diverting energy and resources that could benefit inspiring House candidates in Republican districts, like Ken Harbaugh, an Iraq War veteran who co-founded the Mission Continues, in Ohio-7.

This time, it’s all hands on deck. To flip the House, Democrats and other concerned Americans will have to dig deep in their pockets, subordinate their particular concerns to the cause of winning, and do what it takes to protect democracy.