House Minority Leader Nancy Pelosi (D-Calif.), joined by her top lieutenants, during a news conference on Capitol Hill on May 11. (Andrew Harnik/AP)

Vice President Biden stood on a stage at a Democratic retreat in Baltimore in late January and made a bold prediction: Democrats could win back control of the House of Representatives this year.

“It’s been a tough last couple of cycles,” he said. “But we should get up, man! There’s a real shot here.” Just a handful of the lawmakers clapped.

Biden continued: “I’m confident we’ll win back the Senate, and I think we can make great inroads and maybe win back the House when no one expects it now.”

Nobody applauded, because nobody believed him.

“If you’d have polled the members and asked: ‘Do we have a chance — even an outside chance — to get the majority back?’ At that point, the overwhelming majority would have said no,” said Rep. Denny Heck (D-Wash.), who is in charge of recruiting new Democratic candidates. “I don’t think that is the case now.”

Some Republicans in Congress could be at risk of losing seats, in part because of the party's controversial presidential candidate Donald Trump. These are some the Republicans who are feeling the "Trump effect" the most. (Deirdra O'Regan/The Washington Post)

Facing a 30-seat deficit, Democrats have dramatically improved their odds of retaking the House since Biden’s remarks. Republicans are on the verge of formally nominating Donald Trump, a presidential candidate who remains deeply unpopular among minorities, women and younger voters — just the kind of voters Democrats need to win House seats in swing districts.

Democrats have scrambled to convince enough credible, well-funded candidates to enter key races that could flip control of the chamber — and time is fast running out to recruit more.

Party leaders in Washington had so written off the idea of retaking the majority that a “Majority Project” launched last fall was aimed at elections in 2022 — after the next round of congressional redistricting. Trump’s rise to presumptive GOP nominee sparked a scramble in recent months to recruit Democratic candidates, even in some Republican-leaning districts.

“Donald Trump has been our best recruiting tool,” said Rep. Cheri Bustos (D-Ill.), who helps the party woo new House candidates.

[Can Trump become so unpopular that Democrats could take back the House?]

Democratic consultants think that Trump’s rise has, broadly speaking, tilted the House battlefield in their favor by firming up candidates’ chances in competitive districts, allowing resources to be focused on more marginal seats. Trump, they say, has accelerated the party’s “demographic pivot” into more affluent, better educated, suburban districts. But there are gaping holes that could cost them gains.

“It’s unlikely that Democrats win back the House, but we can’t completely rule it out,” said Nathan Gonzales, editor of the Rothenberg & Gonzales political report. “Donald Trump puts enough volatility into the national political environment that we have to keep an open mind to lots of different scenarios.”

House Minority Leader Nancy Pelosi (D-Calif.) boasted recently to The Washington Post that if the election were held today, ”We would win.” (Andrew Harnik/AP)

Takeover idea gains momentum

Gonzales anticipates that Democrats will gain at least 10 more seats, but he said that picking up the 30 needed for the majority will be “a challenge.”

House Minority Leader Nancy Pelosi (D-Calif.) boasted recently that she thinks she could reclaim the speaker’s gavel. If the election were held today, she said, “We would win. We would pick up more than the 20, we could get to the 30. But it’s not today.”

Republicans, who enjoy a 246-to-188 edge over Democrats, disagree. Katie Martin, communications director for the National Republican Congressional Committee, called talk of a House flip a “far-fetched fantasy.”

“Here in the real world,” she said, “a combination of their recruiting failures in races across the country and their own presidential candidate’s abysmal favorability ratings ensure that Democrats’ chances of winning the majority this year are as laughable as they were in 2012 and 2014.”

In the Orlando area, Democrats are touting Val Demings, a former police chief who is poised to win a safe Democratic seat. But in a neighboring district, the party has not found a challenger for John L. Mica, who represents a district with a fast-growing Latino population and where President Obama tied with Mitt Romney in 2012. The party has until a June 24 filing deadline to find a candidate.

[These new polls should make Democrats feel good about winning the Senate]

In Colorado, Democrats convinced popular former state senator Gail Schwartz to challenge Republican Rep. Scott R. Tipton in the state’s rural western district. But next door in Arizona, Democrats are not mounting a strong challenge to Republican Rep. Martha McSally, who won her district two years ago by just 167 votes but has amassed a nearly $2 million war chest.

In Minnesota, the retirement of Republican Rep. John Kline has increased the likelihood of a Democratic pickup. But in Illinois, the party could not nail down quality recruits in two rural districts along the Mississippi River ahead of a November filing deadline.

And there are problems: Rep. Mark Takai (D-Hawaii) recently announced his retirement due to declining health. Former Democratic congresswoman Colleen Hanabusa has announced plans to run, but the retirement sets up a potentially competitive race in a previously safe district. Actress Melissa Gilbert, who was challenging Rep. Mike Bishop (R-Mich.), also withdrew for health reasons last week, forcing a last-minute scramble for a new candidate that will not be resolved until August because of state ballot laws.

It wasn’t until late March — when David Wasserman, a congressional race forecaster with the nonpartisan Cook Political Report who declared that it was “difficult to be definitive” about ruling out a Democratic takeover — that party regulars began to take the prospect seriously.

Trump’s primary victories also helped Democrats convince candidates to run who might have taken a pass. As winter turned to spring, party strategists held late-night meetings at the Democratic Congressional Campaign Committee headquarters in Washington, poring over polls, turnout models and scenarios that they could use to convince top-tier candidates to run.

They gamed out potential outcomes and how they could benefit Democratic candidates, including a contested convention or a prolonged fight between Trump and Sen. Ted Cruz (R-Tex.). A sudden comeback by Sen. Marco Rubio (R-Fla.), though, would have caused at least some contenders to reconsider running.

‘Worst-case scenario’

In Colorado, Democrats had been trying to convince Schwartz to run for six years, but she repeatedly rebuffed the overtures, citing her work in the state Senate and a desire to stay close to her family. But as Trump’s campaign took off, friends encouraged her to run. She said her husband, “the family gatekeeper,” had been reluctant in the past but encouraged her to run this year — in part because of Trump.

“He recognized that we all have a responsibility to do the most that we can and really saw that we would always regret not taking a run at this seat when we could have a really strong challenge,” she said.

Tipton, her opponent, “is aligned with the Trump ticket,” she said. “It would be a worst-case scenario to see someone like Donald Trump be our president. More importantly, it’s the worst scenario for our region and state to have representation aligned with that ideology.”

Minnesota state Sen. Terri Bonoff, who decided against previous runs for the suburban Minneapolis seat held by Republican Erik Paulsen, jumped in after Democratic Party consultants showed her internal polling giving Hillary Clinton a 22-point edge over Trump in the district.

Bonoff said she opted to run this year partly after watching the Republican presidential debates. Trump and other GOP candidates “insulted women, they insulted immigrants, they talked about building walls and they were competing over who had more credibility in the war of insults,” she said. “That really concerned me.”

Rep. Ben Ray Luján (D-N.M.), chairman of the Democratic Congressional Campaign Committee, shied away from Pelosi’s optimism about reclaiming the majority. But he said that the party would be in a strong position to take advantage of a wave if it happens.

The DCCC recently announced that it raised $8.6 million in April, compared with the NRCC’s $5.4 million. In the first quarter, the DCCC was narrowly outraised by the NRCC.

The House Majority PAC, a pro-Democratic super PAC, also announced Friday that it raised a record $12.8 million. But the super PAC is likely to face strong competition from Republican groups, many of which plan to concentrate spending on congressional races.

[Trump once revealed his income tax returns. They showed he didn’t pay a cent.]

Privately, some Democrats say the party waited too long to find potential candidates.

“All year, party leaders have been saying, ‘We’re going to win the White House, win back the Senate and make gains in the House.’ It’s hard to recruit candidates when you won’t even suggest publicly that you can win,” said one party operative, who requested anonymity in order to speak frankly about strategy.

If Democrats get to the majority, they are going to have to rely on candidates such as Tony Ventrella, who plans to refuse the party’s financial support.

The 71-year-old challenger begins his race against Rep. Dave Reichert in Washington’s solidly Republican 8th Congressional District with enviable name recognition: He spent 27 years on Seattle television stations as a popular sportscaster.

But Ventrella said he will only accept financial contributions from individual donors. He thinks that free publicity because of his name recognition will be key to his victory.

“What you need is three Seahawk players to tweet that you’re a good guy,” he said. “Maybe five or six. If [Seahawks player] Richard Sherman can tweet to his million followers that Tony is okay, then I’m in. That’s all I need.”

Kelsey Snell and Paul Kane contributed to this report.