When the inevitable generational change starts in the top ranks of the House Democrats, Joseph Crowley is planning to be first in line.

Seven months can be more than several lifetimes in politics, of course, and an almost infinite number of internecine machinations will play out before the election — maneuvering not only within the current caucus but also among the candidates who are its most viable prospective new members.

But come the first Wednesday in November, Democrats will know more than whether their next leadership elections will be topped by a contest for minority leader or for speaker of the House.

They are also bound to have a much clearer sense of the plans, and the prospects, that Nancy Pelosi and her two septuagenarian deputies have for the rest of their careers.

Crowley is more than two decades younger than any of them, born 56 years and four weeks ago in a Queens neighborhood he’s represented in Congress since 1999. And he’s well positioned to make the most of any of the likeliest scenarios.

In his second year as chairman of the Democratic Caucus, fourth on the current leadership depth chart, he has all the opportunities he needs to have “What can I do to help you today?” interactions with a broad range of colleagues and candidates — many of them on his travels to campaign for others during the spring congressional recess.

And several lawmakers in the last month have reported that, while he hasn’t made an explicit campaigner’s “ask,” he has left little doubt he’s planning on more formally seeking their support at the earliest available opportunity.

Crowley declined to be interviewed, but on “Fox News Sunday” he gave perhaps the clearest public description yet of his intentions: “I would just wait and see what happened in terms of that, if Nancy Pelosi decided not to run. But if Nancy Pelosi stays, I don’t see a scenario by which I would challenge her for that position.”

Watch: Flashback — Office Space: Joe Crowley’s New York Concert Hall

His bet is that, in making his aspirations quite clear without launching anything close to a formal candidacy, he can go a long way toward clearing the eventual field for himself. But that is by no means a sure thing.

Plenty of other lawmakers have leadership aspirations, of course, some of whom have been less obviously laying groundwork and some of whom are signaling their openness to being tapped as “fresh faces.”

And a caucus where white men are a plurality but not a majority, and where significant differences between the center-left moderates and the hard-left progressives lurk just beneath the surface, may soon enough balk at the idea of having both of the most powerful Democrats at the Capitol be baby boomer white guys from the outer boroughs without a reflexive antipathy to Wall Street — the other, of course, being Brooklyn’s own Charles E. Schumer, the Senate floor leader.

While both are eager and adept bearers of the message that Democrats are the party of the working class, stylistically they reflect very different New York archetypes. While Schumer is more the shambling and intellectual Jewish exterminator’s son, the 6-foot-4 Crowley is the jocular Irish Catholic machine pol and police officer’s son — a crooner and guitarist talented enough to have performed the national anthem at a Knicks game.

When a loss could be a win

Paradoxically, Crowley’s best shot at the pinnacle of partisan power would come if his party failed to make its own.

The current expectation is that the job of minority leader will come open if Democrats don’t win back the House, because Pelosi is already confronting the reality that if that happens and she doesn’t relinquish the job voluntarily, she’ll be denied it with painful clarity. Her 16-year run at the helm of the leadership is extraordinary, and her time as the first female House speaker will always be historic, but hanging on after a fifth straight losing campaign where she’s been a lightning rod for the party would be both unprecedented and legacy-tarnishing.

At that point, Crowley would most likely have to take on Steny H. Hoyer of Maryland, who’s never lost his yearning to occupy the prime position — even if only for a single, transitional term — in part because he’s been No. 2 on every day Pelosi has been No. 1 in the House Democratic command structure.

But Hoyer’s 80th birthday will arrive six months into the next Congress. And for all his aptitude as vote-counter, horse-trader and secret-keeper, younger lawmakers may well conclude his time has passed, because he, too, has been part of a leadership team that has been unable to win back power.

(The same rationale would presumably preclude any successful bid to move up by South Carolina’s James E. Clyburn, who will be 78 in July and since 2007 has been the third-ranking person in leadership and the highest-ranking African-American in congressional history.)

Should Democrats win the midterms, the leadership election dynamic would be shaped by the depth and breadth of their victory.

If it’s an undeniable wave election, where the party picks up perhaps twice as many, or even more, than that bare minimum required to claim the majority — 23 seats — such a blowout win would be proof that GOP demonizing of Pelosi had not worked. And so the roster of her naysayers would likely be more than offset by the roster of returning as well as new members (many of them women) ready to support Pelosi reclaiming the gavel.

But if Democrats win back the House with just a few seats to spare, a crucial bloc of the majority makers will likely have taken swing districts from the GOP after vowing to oppose Pelosi remaining as leader — following the example of the newest House member, Conor Lamb of Pennsylvania. And their votes could seal her fate when combined with the incumbents already in favor of making a change. (Two years ago, 63 voted against her leadership re-election; the only alternative was Ohio’s Tim Ryan after Crowley decided not to press his own challenge.)

It’s also, possible, though, that in either case Pelosi could preempt those discussions — by declaring that winning back the majority was validation enough of her stewardship and that she was ready to turn over the reins and retire on a triumphant note. (This would be an echo of her plans to resign her San Francisco congressional seat had Hillary Clinton won the presidency.)

Watch: Democrats Have At Least 20 House Takeover Opportunities in These 4 States

Leaving the field

Pelosi has been in power so long that only 58 House Democrats seeking re-election this fall have known another floor leader. In the interim, a long line of lawmakers viewed as potential future speakers have taken themselves out of the running. First, Rahm Emanuel left to be White House chief of staff and then mayor of Chicago. Then, Chris Van Hollen opted for a Maryland Senate seat, Xavier Becerra opted to be California attorney general, and Debbie Wasserman Schultz of Florida was fatally sidetracked by her national party chairmanship.

Crowley remains the only member mentioned among that group who’s still got a shot.

To take it will require him to win an 11th term, of course, which is proving more work than usual. The district, which covers northwest Queens and a slice of the Bronx, is lopsidedly Democratic, but in June he faces his first contested primary in 14 years against Alexandria Ocasio-Cortez, a 28-year-old political operative and community organizer running an impassioned grass-roots campaign to his left.

“We have basically, on one side, a multimillion-dollar machine candidate that was never elected, who does not live in the district — he lives in Virginia, his children go to public school in Virginia,” she told the Queens Courier. “It’s really kind of the pinnacle of someone who is a little out of touch but very influential.”

Her reference is to the old-school way Crowley cruised into Congress after a dozen years in the state Assembly: His mentor Thomas Manton, who was both the Queens Democratic chairman as well as a congressman, announced his retirement from the House so late in the 1998 campaign that it was effectively up to him as the party boss to pick a replacement nominee. (Crowley has been county chairman himself since Manton died in 2006.)

Now, he portrays his blue-collar sensibilities as just right for leading his party in combating a president “born on the other side of the tracks” — meaning the Long Island Expressway, which separates Crowley’s Elmhurst from Donald Trump’s Jamaica Estates.

Like the president, Crowley said early in the Trump administration, he’s ready to use colorful language to express outrage and frustration and aims to “talk turkey and talk straight” to workers. “Part of my strength is that I come from the same borough,” he added. “Maybe I sound a little bit like him. But my life could not be more divergent.”