But the party also finds itself with a singular asset that might overpower any of those deep, structural woes: Donald Trump's presidency.
The first 100 days of Trump's tenure in office has infused the progressive base of the Democratic Party with an energy -- and an eagerness to fight -- that party elders have never before seen.
The women's marches and the emergence of an even broader-based, liberal version of the tea party led by new groups like Indivisible, have brought into the party new activists willing to do the grunt work of organizing locally.
That energy has manifested itself in massive turnouts even at far-flung town halls hosted by Republican members of Congress, as well as in an unprecedented non-election year fundraising surge for progressive organizations. Other new groups, including Run for Something, are helping recruit and train candidates -- some of whom will compete in places previously ignored by Democrats.
One thing is holding it all together: Trump.
Washington Gov. Jay Inslee compared Trump's presidency to a mix of "comic opera and tragedy."
"You almost expect him to say, 'Who knew the North and South was so complicated?'" Inslee said in an interview, referring to Trump's claim he'd sent an "armada" to the Korean peninsula when in fact the aircraft carrier was en route to the Indian Ocean
. "You sort of expect him to nominate Bill O'Reilly for man of the year."
Ben Ray Lujan, the chairman of the Democratic Congressional Campaign Committee -- the House Democrats' campaign arm -- said in the party's weekly address marking Trump's 100 days in office that "it seems like President Trump spends more time golfing than governing."
While Democrats have a common enemy, they still don't have a common message -- or a single leader.
With Barack Obama enjoying retirement and the Clintons off politics' main stage, Democrats no longer have a star figure to counterbalance Trump.
Senate Minority Leader Chuck Schumer, D-New York, was successfully able to muster a filibuster against Trump Supreme Court nominee Neil Gorsuch, forcing Republicans to invoke the "nuclear option" taking away the filibuster for future high court picks. And House Minority Leader Nancy Pelosi, D-California, has kept her ranks from supporting Trump.
Yet those figures help Democrats win process battles -- not identify a positive message to sell to the nation.
Others on Capitol Hill -- particularly Massachusetts Sen. Elizabeth Warren
, New Jersey Sen. Cory Booker, New York Sen. Kirsten Gillibrand and California Sen. Kamala Harris -- are being looked to for leadership. Gillibrand won progressives' praise by casting the most "no" votes against Trump's Cabinet picks.
Vermont Sen. Bernie Sanders has by far the biggest megaphone of anyone on the left. Yet in an interview alongside new Democratic National Committee chair Tom Perez in the middle of their joint unity tour, Sanders told MSNBC he isn't a Democrat -- he's an independent.
Still, Democrats insist they aren't worried. Some party officials and Democratic veterans pointed to the Republican rise of the tea party in 2009 and 2010, noting that its messages never really developed beyond stopping Obama and his push for health care reform.
Trump isn't likely to stop provoking liberals' ire, those Democrats said.
"There's like five assaults on progressive values a day, depending on the tweets," said Neera Tanden, the president of the Center for American Progress. "He's doing nothing to make anyone do anything but dislike him."
Democrats are now largely focused on special elections for House seats vacated by Trump's Cabinet nominees.
The party nearly pulled off a shocker in Kansas
-- with no investment from the national party. Then, in Georgia, online fundraising superstar Jon Ossoff came within 2 percentage points
of capturing what was once Newt Gingrich's seat in Congress -- and has another shot in a June runoff.
Those close results in normally deep-red districts have buoyed Democrats' hopes for the 2018 midterm elections -- even if party activists were disappointed not to net any wins yet.
"The current playing field -- this handful of special elections -- is on a tiny, unrepresentative patch of the country that is far more Republican than the nation as a whole," said David Nir, the political director for Daily Kos, the liberal blog that helped Ossoff raise an eye-popping $8.3 million in 2017's first quarter.
"But plenty of Republicans who sit in much more vulnerable districts will be up for re-election next year," Nir said. "If they slip by anywhere near as a big a margin as the GOP did (in Georgia and Kansas), a lot of them are going to lose. And DC Republicans can't go all in with millions in spending to save every at-risk GOP incumbent next year."
As for leaders, Perez has taken the helm of the DNC and is now in his second month attempting to rebuild the organization. Much of the behind-the-scenes work of preparing the infrastructure for the 2018 midterms and the 2020 presidential race could fall to him.
Other Democratic organizations are also preparing to play new roles. The super PAC Priorities USA brought Democratic super lawyer Marc Elias onto its board and is focusing on voting access. Former Attorney General Eric Holder is leading a new group's efforts to fight gerrymandering
in courts and back Democratic state lawmakers so the party has more say in the redistricting process.
Tanden, meanwhile, has organized a May "Ideas Conference" with a star-studded lineup that looks like the first cattle call of the 2020 Democratic presidential primary.
But Democrats say they're not worried the party doesn't have a single standard-bearer today.
"The heroes are on the street right now," said Inslee, who led the legal battle against Trump's executive order banning travel from seven majority Muslim nations.
Inslee recalled a ferry ride to the women's march in January, where he saw an old friend who had never been politically active. She was wearing a pink hat -- and had brought 10 of her friends with her.
"It's been very successful organically without any particular strategic thought," Inslee said. "It's been a very gut-level, sincere, powerful effort to resist a departure from basic American values. And the fact that it has been organic and natural without a dime's worth of provocation is pretty amazing."