As if Democrats don’t have enough to keep them up nights, here’s something beyond frightful visions of a Trump victory: a Republican trifecta in Washington.

Joe Biden’s calamitous debate performance and the burgeoning concerns about his age and acuity aren’t just undercutting his chances at a second term. They’re also threatening to drag down his party and thwart Democratic efforts to hold on to the Senate and flip control of the House.

That helps explain the party’s Great Freak-Out and why so many Democratic lawmakers desperately wish Biden would stand aside and abandon his reelection effort. (Even if they’re not willing to publicly say so. We’re not seeing a seeing a lot of backbone or intestinal fortitude at the moment.)

“What’s going on right now in no way, shape or form is going to help those running for reelection,” said Jim Manley, who spent decades in the Senate as a top leadership aide.

Nonpartisan election handicappers — those who make a living offering measured and judicious analyses of contests nationwide — agree. The existential angst surrounding Biden and his durability, both physical and political, isn’t helping his party or its candidates, they say (being measured and putting it very mildly).

“The question is: How big of a hole is Biden digging for them at the top of the ticket that they need to climb out of in their own races?” said Nathan Gonzales, editor and publisher of Inside Elections.

Herewith, some obligatory caveats:

• It’s still a long way to November.
• There is no certainty that replacing Biden as the Democratic nominee won’t make things worse.
• Donald Trump could do something so awful and odious that voters will recoil en masse, sending him and fellow Republicans to an epic thrashing in November— though I wouldn’t hold your breath on this one.

For now at least, Democrats suddenly face a much steeper climb to prevent a complete GOP takeover of Washington, which includes a submissive, Trump-friendly Supreme Court.

It was always going to be tough for Democrats to keep control of the Senate. They hold a reed-thin 51-49 advantage, counting three independents who caucus with them. They have to defend more than twice as many seats as Republicans — 23 to 11 — and several of those are in states that Trump won handily in 2020.

West Virginia Sen. Joe Manchin at a political event in New Hampshire in January.

(Charles Krupa / Associated Press)

It’s a virtual certainty that Republicans will take the Senate seat held by West Virginia’s Joe Manchin III, Trump having carried the state by nearly 40 percentage points.

That would put the chamber at 50 to 50. Under those circumstances, Democrats could keep control if they win the White House, as the vice president serves as tiebreaker. But just reaching a 50-50 split would require two of Democrats’ most endangered incumbents, Jon Tester of Montana and Sherrod Brown of Ohio, to prevail in states Trump won decisively last time.

Surveys have consistently shown Democrats across the country outpolling the president — which shows how specific Biden’s problems are to the aged incumbent. Jessica Taylor, who analyzes Senate races for the Cook Political Report with Amy Walter, says the question is: When does Biden become too big of a drag for Democratic candidates to overcome?

“You can outrun the president by 5, 6, 7 points,” Taylor said — but how much more? “Where,” she asked, “does the gravitational pull overtake even a Democratic incumbent that runs a perfect race?”

Democrats talk optimistically about flipping Senate seats in Republican-leaning Florida and Texas, offsetting possible losses elsewhere. But that would require not just fighting Biden’s downdraft, but also overcoming the country’s increasingly partisan voting habits.

In 2016, for the first time, every Senate contest went the same direction as the presidential race. Meaning if Trump carried a state, the seat went to a Republican. If Hillary Clinton won, the seat went Democratic. The pattern repeated in 2020, with one exception, Maine.

Increasingly, the ticket-splitting American is becoming a rare bird.

The fight for the House looks to be much closer.

Democrats need a gain of just four seats to win control. The Cook Report ranks 44 seats as competitive — 24 of them held by Democrats and 20 by Republicans. (Inside Elections sees a more expansive field, with 71 seats in play —39 Democratic and 32 Republican.)

The problem for Democrats is a distinct mood shift after Biden’s dreadful performance in Atlanta and his halting remediation efforts since.

President Biden arrives to attend a mass at St. Joseph on the Brandywine Catholic Church in Wilmington, Del., on Saturday.

(Manuel Balce Ceneta / Associated Press)

“I think the debate has created a base problem,” said David Wasserman, who tracks House races for the Cook Report. By that he means the prospect of fatalistic Democratic and Democratic-leaning voters sitting out this November, sinking the party’s candidates.

All of that gloom and doom aside, there is the merest silver lining for beleaguered Democrats, regardless of whether Biden stays dug in and remains atop their ticket.

If defeat in November seems certain, independent voters may swing toward Democrats to keep Republicans from gaining control of the House and Senate and allowing a revivified Trump to run roughshod.

That checks-and-balance argument was employed by Republicans — subtly — in 1996, when it was obvious the GOP nominee, Bob Dole, was about to lose to President Clinton. Did it work? Hard to say. But Republicans did manage to gain two Senate seats and lose only two in the House, keeping control of both chambers even as Clinton rolled to reelection.

But that’s looking on the bright side for Democrats.

If that’s their best hope, the party is in real trouble.