The party taking shape will challenge the GOP with a distinct populist tilt, marking a departure from the centrist views that had dominated during the era of Bill Clinton and Barack Obama. This year's candidates have largely endorsed universal health care, a $15 minimum wage, easing the financial burden for college students and tougher gun control.
But there is sharp disagreement as more than 1,100 candidates have filed, with disputes over tactics - how to criticize Trump or how best to talk about issues - and sparring over who should be the standard-bearers, either first-time hopefuls or experienced politicians.
In Kentucky, for example, a female fighter pilot is lashing out at Democratic leaders after they recruited a wealthy mayor for the race against a Republican congressman who has staunchly supported Trump's agenda.
In Indiana, a liberal attorney talking about censuring the president has stoked a fierce fight over how strident the Democratic resistance should be.
In interviews with dozens of candidates and voters in six districts - urban, suburban, predominantly rural, college town - there was one unifying factor: an intense desire to win in November. But there was real fear that party fissures could prevent Democrats from netting the 23 seats for a majority in the House.
The party is still recovering from the bitter 2016 fight between Hillary Clinton and Bernie Sanders and faces the midterms and 2020 presidential race with no clear national leader. Democrats are determined to claw back after a decade of devastating losses in congressional races and statehouses.
"People are hungry for change, and they believe and they know that the ultimate protest is winning elections," said Mel Hall, a Democratic candidate in Indiana.
The day after Trump was elected, Amy McGrath was dumbfounded.
"I woke up the next morning with a hole in my heart. I felt like, 'What just happened? How did we get here?' " the former Marine Corps pilot recalled.
These days, McGrath is flummoxed by something else: the Democratic establishment, which she has accused of lining up against her candidacy.
Amid the distilleries and horse farms that dot a district stretching from the urban center of Lexington to rural areas, McGrath and five other Democrats have entered the race to challenge three-term Republican Rep. Garland "Andy" Barr.
Like so many others, McGrath was itching to do something after Trump won. So she moved back to Kentucky and ran in a district Trump won by 15 points. She became a national sensation when she released a slick launch video touting her time as a fighter pilot.
It wasn't enough to satisfy party power brokers, most notably those at the Democratic Congressional Campaign Committee.
"Instead, they went out and recruited the mayor of Lexington to run against me," said McGrath, 42. "I mean, it's like, what are you guys doing?"
The mayor, Jim Gray, is a wealthy former construction executive with an ability to fund his own campaign. He also is a familiar name, losing to Sen. Rand Paul, R, in 2016, but carrying the 6th District. Gray also is openly gay, which he says is not an issue, even in this conservative area.
Gray, who launched his campaign months after McGrath, acknowledged that people at the DCCC "gave me some encouragement" to run. He noted the committee has not officially endorsed him. The DCCC did not comment.
To hear Gray and McGrath talk about issues is to hear echoing voices. Neither wants to go to Washington just to fight Trump; both see opportunities to work with him. Neither will commit to voting for Nancy Pelosi as House Democratic leader. Both are staunch defenders of the Affordable Care Act, though they stop short of embracing a single-payer health-care system.
So they have taken to highlighting their personal backgrounds in an effort to stand out ahead of the May 22 primary.
"I feel like what our country is experiencing today really calls on leadership, and it really calls on experience," Gray said in an interview at a coffee shop in Lexington.
Gray, 64, repeatedly highlighted his tenure as mayor and his business accomplishments.
In a telephone interview, McGrath emphasized her unique background as an asset.
"We cannot as Democrats keep pinning our hopes on older, rich, white guys to save us," she said. What Democrats need, she said, "is people from all walks of life."
One woman described choosing a primary candidate as "hard and stressful." Winning in November was on everyone's mind.
"If somebody can give me polls and numbers and an idea of who can go against Barr and who's really got the biggest chance of beating him, I would be comfortable with any" of the three leading candidates, said Cathie Griggs, 64, a retired speech therapist. "People want to vote now," she added.
The question posed to three Democratic congressional candidates at a debate in South Bend, Indiana, was supposed to be a softball: "If you are not the winner of the Democratic primary, will you actively support the winner?"
Pat Hackett, a 58-year-old lawyer and first-time candidate seeking the seat held by three-term GOP Rep. Jackie Walorski, kept silent for 10 seconds before responding: "Yes, I'm a Democrat, and a Democrat is preferable to Jackie Walorski, but my statement shouldn't be construed as it doesn't matter. It matters enormously. I'm the Democrat on this stage."
Her equivocation enraged fellow candidates and party officials in Indiana's 2nd District, where six Democrats are seeking nomination in the May 8 primary.
Although party leaders see a prime opportunity to flip a GOP seat that has long been considered out of reach, energized liberals are making clear that they are not going to keep quiet and happily back a centrist, soft-edged candidate.
While party organizations have made no endorsement, the candidate with clear backing from the Democratic establishment is Mel Hall, a Methodist minister turned health-care executive who describes himself as a "ruthless pragmatist."
"Certainly people talk about tweets, and he does create distractions, and I think there's probably a slice of maybe the far left that do talk maybe a little more vociferously," Hall, 64, said in an interview. "But what people in this district want are someone who shows up and gets something done."
Hall is facing competition from Yatish Joshi. The 67-year-old self-made immigrant business executive and local philanthropist has loaned his campaign $200,000 and is seeking to upend a national Democratic platform that he calls "obsolete." He also openly resists a president he sees as rolling back American ideals. Three other Democrats will be on the ballot but have not mounted extensive campaigns.
On the issues, Hackett and Joshi want a "Medicare for All" single-payer health-care system, while Hall supports revising the Affordable Care Act and lowering the cost of prescription drugs and medical equipment. Hackett and Joshi call for free college and forgiving student debt, while Hall calls for refinancing existing debt and capping free tuition for wealthier households. And on gun control, all three candidates support banning high-capacity magazines and instituting universal background checks, but unlike the others, Hall stops short of supporting an assault weapons ban.
Hackett, who suggests censuring Trump, and Joshi argue that running an unabashedly liberal campaign will get a group of voters to the polls who tend to skip elections when their choices range from the political center to the hard right. But Democratic officials like Jason Critchlow, the St. Joseph County party chairman, fear Hackett is starting down a path that, should she win the nomination, could make it impossible for Democrats to oust Walorski.
"You have this sort of new breed of activist," he said, adding, "for some reason, it's very important to them that they have this enemy within - not just Republicans and not just conservatives."
Bob Settle, a retired civil servant, held up a copy of two-term Republican Rep. Barbara Comstock's latest newsletter, which he considered light on accomplishments. "I want a candidate who can beat her," he said at a recent meeting of local Democrats.
His pick, in a field of seven, is state Sen. Jennifer Wexton, a former prosecutor with deep roots in Loudoun County. He likes that she is well-known. Wexton has the support of Gov. Ralph Northam as well as Democratic Reps. Gerald Connolly and A. Donald McEachin.
"You can be in favor of banning assault weapons, you can be in favor of universal health care, you can be in favor of everything in the world," said Settle, 70, "but if you can't beat Barbara Comstock, you're not going to do any good."
Wexton makes a succinct pitch about her experience as a legislator passing bills on day-care regulation, the opioid crisis and domestic violence, issues that appeal to suburban moms, who were key to Northam's win.
"So why me? I have shown that I have what it takes to run and win challenging races in the district and then to govern once I get there," she told three dozen Democrats at the recent committee meeting Settle attended.
But voters have plenty of choices in a district that includes suburbs of the nation's capital and which Clinton won by 10 points. And the pressure is on to defeat Comstock, whom one nonpartisan analyst rated as the most vulnerable Republican incumbent.
John Nee, the local Democratic Party chairman, gave strict instructions to seven candidates for a newly drawn congressional seat: Introduce yourself, your background, and then tell us your top three issues.
The first response seemed predictable. "Pushing back against the Trump administration and the Republican Congress that has been enabling it," said Mary Gay Scanlon, a lawyer, tapping into the anti-Trump energy of the 60 to 70 activists who trudged through a cold Sunday night to a township hall for a candidate forum.
What came next was less predictable. One by one, the remaining six candidates focused on key issues. Gun control ranked high. A couple chose creating a single-payer health-care system. Nearly all mentioned jobs and education.
No one else mentioned Trump.
In fact, throughout the 75-minute forum, the seven candidates - only half the field - largely ignored the elephant in the room. Democrats in this onetime GOP bastion - where new liberal energy and a redrawn district has Democrats champing for victory - have a baseline assumption that anyone running for office now despises Trump and will work to rein in his administration in Congress.
Faced with seven candidates, Democratic voters in New York's 19th Congressional District had one question: Who could win in November in this rural district south of Albany?
"Who can beat [John] Faso?" asked resident Dorothy Dow Crane, 73. "Any of them would be fine. It's about who's electable."
At a crowded voter forum, there was little daylight between the candidates on issues. They favored a ban on assault weapons, reversing the Republican tax cuts and instituting Medicare for all, though they differed on how quickly such a monumental health-care change could occur.
Democratic candidates and voters were fed up with Trump, but months before the primary, few were focused on him. The president, the impetus for so many people entering the race, had faded into the background.
"I've said for the better part of a year that it's not about Trump," said Brian Flynn, a medical device company founder who entered the race in September. "Trump's a symptom, not the cause."
At Dietz Stadium Diner, two voters said excitedly that they'd just settled in the district from Brooklyn and were desperate for a Congress that could stop Trump.
"I worry about my grandchildren," said Marilyn Ippolito, 71. "I don't want them to die in a nuclear war."
When Sam Jammal was done speaking, he put the mic down. Then, people stood up and cheered.
Jammal, one of six Democrats running in California's 39th District, had just delivered an impassioned plea on behalf of undocumented immigrants - a topic that energized the crowd at a Thursday candidate forum in Fullerton.
"If you're eating a salad, that salad was picked by immigrants!" the attorney for technology and clean energy companies said, his voice rising as he began to speak over sustained applause. "We can't just abandon immigrants because of a talking point in a campaign."
Jammal is running for the seat that encompasses parts of Los Angeles, Orange and San Bernardino counties. At the forum, he and two other Democratic hopefuls toed the liberal line on every issue that came up, including health care, the environment, the Republican tax overhaul and protecting young undocumented immigrants. They opposed Trump on everything.
The race to succeed retiring Republican Rep. Edward Royce is one of Democrats' best pickup opportunities this year. The first hurdle they must clear is a nonpartisan primary on June 5. The top two finishers, regardless of party affiliation, will advance to the general election.
"I want somebody who's elected to stand up to Trump. Trump is a walking disaster," said Julie Suchard of Placentia, a former Republican. "I can't tell you how many times where I check my phone in the morning when I wake up, and it's like, 'Oh god, what did he tweet? What is he going to do to this country?' "
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