Nancy Pelosi, the House Democratic leader, will be 77 next year. Steny Hoyer, her deputy, will be 78. Jim Clyburn, the No. 3 Democratic leader, will be 77.

Their current ages, if combined, would date back to before 1787, the year George Washington presided over the signing of the Constitution.

It is time for them to go.

This is not to take away anything from their accomplishments. Hoyer is one of the most decent and genial people in politics. Pelosi, the first woman to be speaker of the House, has been enormously effective in unifying her Democratic caucus.

But let's be honest. Barring a political earthquake, the next plausible chance for Democrats to take over the House is in 2022, after the 2020 Census and a redrawing of district lines that have protected Republicans. By then, Pelosi and Clyburn would be 83, Hoyer 84.

Democrats would benefit from some fresh blood to take on Donald Trump, the oldest president ever elected for the first time, and to revive enthusiasm among millennials, who didn't turn out in the numbers Democrats needed.

Pelosi's leadership team also misplayed the 2016 election. Its campaign arm, the Democratic Congressional Campaign Committee, insisted on a strategy of tying each Republican to Trump, even though, as I wrote at the time, evidence showed that this wouldn't work. Democrats gained a paltry six seats.

But the most compelling reason for them to step aside is generational. All three are technically from the so-called Silent Generation, but they are the vanguard of the baby boom generation that dominates Congress. Pelosi has been emblematic of that generation's governing style on both sides: Passionately ideological and unyielding, they presided over cultural warfare and dysfunction.

This is why Tim Ryan's long-shot challenge to Pelosi is welcome. The 43-year-old backbencher from the Youngstown, Ohio, area won't win, but he is doing Democrats a favor by forcing them to think about the desirability of keeping their septuagenarian leaders in place. Hopefully it will hasten their succession plans — Pelosi's iron grip over the caucus has made this difficult — so that all three can step down soon. Among those Pelosi is grooming: Joe Crowley, 54; Linda Sanchez, 47; Joe Kennedy III, 36; Eric Swalwell, 36; Katherine Clark, 53; and Matt Cartwright, 55.

Ryan isn't a flawless candidate. He's only a recent convert to supporting abortion rights. His detractors point out that in his 14 years in the House, he has won passage of just three minor bills. Opponents grumble that his real purpose in challenging Pelosi is to raise his visibility for a gubernatorial run in 2018, when Ohio Gov. John Kasich will be term-limited.

But Ryan is an interesting character, a former high-school quarterback who drinks at the Open Hearth bar on Steel Street in Youngstown and is the author of books on the benefits of meditation and healthy eating. And this Rust Belt politician's central critique of his party is correct: A populist economic message was secondary to cultural issues in the 2016 election and during much of the Obama presidency.

Ryan, who won 68 percent of the vote in a district where Clinton underperformed relative to Democrats in the past, explained that Trump's blue-collar voters "are the guys I drink beer with. These are my buddies I watch football with. I don't need to run a focus group." His bar-stool focus group tells him that voters didn't love Trump but wanted to say "go screw yourself" to the establishment.

In his telling, he has no policy differences with Pelosi. "I can't think of one, other than emphasis," he says. And that emphasis is squarely on economics.

His solution: "Get rid of the perception that we're tied to Wall Street, that we're coastal elites and that we're more concerned with the donor class than the working class." His specific remedies are less clear, a scattered assortment of employee stock ownership plans, wind turbines and hydraulics, with some salty, steelworker language mixed in.

In Tim Ryan, I hear a pragmatism that is typical of his generation (and mine). He finds Trump's racial politics "appalling" but finds Democrats' "slicing the pie up" between working-class white, black and Hispanic Americans to be idiotic. Of the other Ryan, Republican House Speaker Paul Ryan, the Democrat attests: "I like him. ... He's a nice guy. I don't demonize him."

Nor would Republicans, after years of demonizing a San Francisco liberal, find it as easy to demonize this son of Ohio. "At least make them do it again to someone else," Ryan says. "Hey, why not me?"

Follow Dana Milbank on Twitter, @Milbank.