Three highly-touted liberal House candidates — Jessica Cisneros in Texas, Robert Emmons in Illinois, and Morgan Harper in Ohio — lost their primary races against more moderate members of Congress. They are now playing defense as Rep. Rashida Tlaib, one of the four members of the “squad,” faces a stiff primary challenge in Michigan. And Sen. Ed Markey (D-Mass), who’s managed a late-career makeover into a left-wing darling, with endorsements from Rep. Alexandria Ocasio-Cortez (D-N.Y.) and other progressive groups, is consistently outpolled by primary challenger, Rep. Joe Kennedy (D-Mass.).

The movement has also had limited influence on the proposals House Democrats have put forward to address the coronavirus, with leadership rejecting its most ambitious ideas.

The abrupt reversal of fortune has prompted introspection among many left-wing activists, who only three months ago were confident that the future of the Democratic Party was theirs.

Interviews with more than 15 left-wing leaders — including grass-roots organizers, down-ballot candidates and former aides to Sanders and Sen. Elizabeth Warren — revealed strife over what went wrong and what to do next.

Some asserted that Sanders' and other challengers' losses were just the result of campaign missteps and that their ideas remain popular. They argued that progressives still are on track to take over the party in the coming years and are looking to other down-ballot races this year to make a mark.

But others were less sanguine about the left's future, after their losses this year and in the 2018 midterms. Several pointed to progressives' failure to make serious inroads with older black voters, the most loyal base of the Democratic primary. And some said they fear the Democratic Party is drifting away from the more class-based politics they are advocating for, as national Democrats increasingly target wealthier, more educated suburban voters to make up for losses in rural areas.

These clashes and internal debates are beginning to set the course of the post-Sanders left and could be key to whether the young, demoralized progressives remain engaged or withdraw.

Even the left-wing’s highest profile win this year was less of a triumph than the left has spun it as. Marie Newman, who had a Sanders-esque platform — supporting the Green New Deal and Medicare for All — defeated Illinois Rep. Dan Lipinski in March. While many left-wing groups backed her, her victory was also attributed to support from more mainstream liberal groups like EMILY’s List and Planned Parenthood and several presidential candidates.

Perhaps more concerning for the left, her base of support more closely resembled Joe Biden’s than Bernie Sanders’ hopes for a working-class coalition. Newman focused on suburban women, while Lipinski’s base was made of more “traditional Democrats...very much more non-college, older, sort of the traditional white ethnic vote of Chicago,” according to Donna Victoria, Newman’s pollster.

Some progressives compare the recent defeats to Barry Goldwater’s drubbing in 1964 — a temporary setback but a harbinger for what became the Reagan Revolution. They argued that the rise of the left will continue as young Democrats who overwhelmingly voted for Sanders become an increasing share of the party.

“I do believe progressives are in the ascendancy in the Democratic Party and we are still in the midst of that transition,” said Faiz Shakir, Sanders campaign manager, who described the recent losses as “growing pains.” He pointed to Biden and other Democrats who have embraced progressive policies far to the left of where the party was a decade ago as evidence of the left's expanding influence.

But others see a need to significantly revamp the left’s approach after its failure to make significant inroads with older black voters. Some former Sanders aides believe that portraying the party itself as an enemy alienated some black voters who strongly identify as Democrats.

“We tried very, very hard in a lot of different ways to make the appeal to older African-American voters,” Shakir said, adding that growing support for Medicare for All among black voters in states they lost offers reason for hope.

"A majority of Democratic primary voters agree with us on the issues but see the main conflict in American politics as being between the ‘red team’ and the ‘blue team,’ said Claire Sandberg, Sanders' former national organizing director. “I think we’ve seen that leading with an anti-establishment message can be counterproductive because it allows the establishment to paint us as divisive and disloyal, which hurts us with the high propensity older voters we need to do better with to win Democratic primaries."

Others expressed concern that the party’s further expansion into the suburbs is a sign that the class-focused politics of the left represent the past, rather than the future, of the party.

On one matter, they all agreed: They are desperate for a win. Many are scouring the remaining congressional primaries and state legislature races for opportunities. Sanders himself endorsed three statehouse candidates last week — two primary challengers in Michigan and Pennsylvania and one progressive in a contested race for an open seat in Missouri.

One of those candidates said that the left needs to realize it can’t win on its own and suggested Newman's victory could be a blueprint.