Conor Lamb had a problem. When the Democratic congressional candidate knocked on doors in his heavily Republican western Pennsylvania district, he got strongly positive responses from voters—except on one subject. “People would say, ‘You know, I just wish you were not with Pelosi,’” a campaign adviser says. “It was really the only negative thing Conor would hear.” Lamb reminded wary voters that he had told a local newspaper he would not support keeping Nancy Pelosi as the House Democratic leader, if Lamb won his race. But who reads anymore? And the Republicans were in the process of dumping $7 million into TV ads that tried to make Lamb look like the California congresswoman’s son.

So with less than a month to go until the special election, Lamb responded in kind with a TV commercial of his own, emphatically distancing himself from Pelosi. Lamb beat Rick Saccone by a mere 627 votes, making him the latest optimistic evidence for Democrats who want to believe a blue wave is building toward this fall’s midterms—and making Lamb a problem for Pelosi’s dream of riding that wave back into power as speaker of the House next January. At least a dozen Democratic candidates running in Trump-friendly districts from California to Kansas have followed Lamb’s lead and said they favor ditching Pelosi.

“If the blue wave comes in, the battle over who should be speaker would happen in advance of when we come back in January, and it would probably be rough,” one Democratic House incumbent says. “But it’s too important for us to win the House to engage in any plotting and planning and measuring the drapes before we actually win it.”

Caution is indeed wise: Republicans have cut the generic congressional-ballot gap to six points, and President Donald Trump’s approval rating has lately crept back above 40 percent. But the plotting and planning inside House Democratic circles is nevertheless well underway. “I would love to see Joe Crowley as speaker, and he is the best positioned, if it’s not Pelosi,” one Democratic congressional strategist says. “He’s been working to put that in place for 10 years.” Crowley, now in his 10th term, is well-liked by his colleagues and is a shrewd operator, commanding one of New York City’s last political machines. At 56, Crowley can argue that he’d be a significant generational change from the 78-year-old Pelosi. On the other hand: “If the blue wave comes in and we’re talking about new blood, are we really going to elect another middle-aged white guy from New York as the other leader in Congress?” another House operative says.