Conor Lamb’s stunning showing in the Pennsylvania special election showed the blue wave building as the November midterms approach. But will the debate over what the Democratic Party is for undermine the unity needed to stop Donald Trump and take back the Congress?

Lamb’s remarkable surge in a district that favored Donald Trump by twenty points proves the “Resistance” is real. Republicans outspent Lamb and his allies by a five-to-one margin, and threw their entire playbook at him. None of it worked. Over 100 Republican-held districts more more competitive than the one Lamb now represents, and the panic in Republican circles is surely real.

House Speaker Paul Ryan sought to dismiss the result by arguing Lamb masqueraded as a conservative. In a somewhat similar vein, some pundits and Democratic party officials suggested Lamb’s victory validates the Democratic Congressional Campaign Committee’s strategy of finding candidates that “fit their districts,” which is often code for finding more conservative or corporate Democrats.

While Lamb said he wouldn’t vote for Nancy Pelosi to lead the party and was personally pro-gun and opposed to abortion, the notion that he ran as a conservative is fanciful. Jon Favreau, Obama’s former speech writer, demolished it in one tweet, noting that Lamb campaigned for universal health care, against Trump’s tax cut, for expanded background checks, for stronger unions, against cuts to Social Security, for a woman’s right to choose and for medical marijuana.

Lamb ran as a champion of working people. He railed against House Speaker Paul Ryan for passing tax cuts for the rich and corporations while pushing to deep cuts in Social Security and Medicare. He supported Trump’s tariffs while campaigning against our failed corporate trade policies. He championed unions against an opponent who favored right-to-work legislation.

Lamb’s campaign was fueled by small donations and a field operation bolstered by unions. The DCCC largely stayed out of the race until late, and it’s possible it raised more money off the race than it actually put into it. Turnout in the race showed not only that liberal voters are mobilized against Trump and Republicans, but that a Democrat with a strong, progressive economic message can cut into the long-established Republican support.

The annual Progressive Caucus Center Strategy Summit last weekend showcased the growing capacity and confidence of progressive movements and leaders in driving the demand for fundamental change. The gathering showcased the movements and the leadership that are lifting the blue wave.

The Congressional Progressive Caucus is the largest and most diverse group in the House. Its members tend to come from strong Democratic districts. They are increasingly united behind a bold populist agenda – fair trade, $15.00 minimum wage, Medicare for All, expand Social Security, tuition free college, support for worker rights and unions, public investment to rebuild America and drive a Green New Deal.

The summit featured the leaders of the CPC as well as progressive champions like Senator Elizabeth Warren. Bernie Sanders spoke by video. All called for both mobilizing against Trump and Republicans and demanding fundamental reform. Warren was saluted for her courage in calling out Democratic Senators who have lined up with the big banks to weaken bank regulation.

Chris Shelton, President of the Communications Workers of America, summarized the challenge most forcefully in his keynote address. “The fight for our country’s future,” he declared, “starts with The Resistance, standing up every day against the petulant, racist, fascist-coddling, phony populist, pro corporate, lying lunacy that cascades out of 1600 Pennsylvania Avenue on an hour-by-hour basis.”

At the same time, he argued, progressive movements must continue “the fight to construct a set of visionary, value-based progressive populist politics that can win back a governing majority in this country.” That’s an agenda that “puts Main Street before Wall Street, that is serious about fighting for racial, gender and environmental justice, that is deeply committed to restoring [our] democracy… If we don’t deliver a positive message that resonates with working people in this country, then we will continue to lose.”

Shelton contrasted Wall Street Democrats with “poor people, working people, people of color, young people, women, LGBT people, immigrants” who must be the heart and soul of the Democratic party. He called on Democrats to lead on raising the wages of American workers, on stopping the offshoring of jobs, and on protecting unions and worker rights at the workplace.

Shelton admits that too many of his members voted for Trump, in order to “shake things up.” Trump is trying to lock in that working class support with his trade, tariff and tax postures, as well as uglier race-bait appeals. Shelton argues that the only answer is a bold agenda for economic justice that appeals to working people of all races, genders and sexual preferences. A bold reform agenda expands the appeal of Democratic candidates rather than limiting it.

The CPC is driving that agenda inside the Congress, as its PAC is raising new resources to support progressive candidates in the field. The CPC’s infrastructure bill will largely define the Democratic response to Trump’s sham proposals. Its trade principles offer Democrats an alternative to the failed strategy of the past. Its People’s Budget is slowly gaining traction among Democrats. At the summit, Keith Ellison announced he would spearhead the push for Medicare for All.

The CPCC summit also highlighted the movements that are mobilizing across the country. The victorious West Virginia teachers strike will inspire teachers and other workers across the country. The Women’s March will mobilize in 10 states and Planned Parenthood announced a $20 million electoral program. Progressive groups like Move on, Democrats for America, Working Families Party, the Progressive Congress Change Committee, People’s Action, Our Revolution, Indivisible, Justice Democrats and others are building capacity to recruit and support insurgent candidates.

If anything, the problem is that these progressive efforts are too weak, not too strong. Our Revolution is focused more on state and local races than on the congressional battle. The other groups have a limited slate of insurgents that they are supporting. Unions and the CPC PAC are more comfortable operating in the general election rather than in primary fights.

Democratic leaders got the message of the 2016 election: voters are looking for big change. Senate leader Chuck Schumer brought Elizabeth Warren and Bernie Sanders into his leadership group. House leader Nancy Pelosi came to the CPC Summit to champion the need for a bold economic agenda.

Yet, the DCCC and the party pros remain wedded to the old ways of doing business. They recruit candidates with deep pockets or the ability to raise big money and tend to seek out veterans and social conservatives for contested districts. Establishment Democrats also try to limit the financial drain of contested primaries by undermining candidates like Laura Moser in Texas who might win a primary, but by DCCC calculation, are less likely to prevail in the general election.

This isn’t going to cut it. The DCCC’s track record for picking “winners” doesn’t demand respect. As the attack on Moser showed, efforts to undermine insurgents are likely to backfire. Midterm elections are about passion and energy. Democrats need a sea change, and the resistance to Trump is lifting the tide. What the Lamb victory shows is that Democrats of all stripes are ready to come out in large numbers to take back the Congress and confront Trump. Unity is more likely if the DCCC gets out of the way and allows voters to decide who will carry their banner.