FILE - In this April 4, 2018, file photo, Sen. Bernie Sanders, I-Vt., speaks at a rally commemorating the 50th anniversary of the assassination of the Martin Luther King Jr. in Memphis, Tenn. Hundreds of liberal candidates are streaming into Washington this week as the Democratic Party’s far left flank intensifies in its push to seize control of Congress, statehouses and local governments across the country this fall. (AP Photo/Mark Humphrey, File)

WASHINGTON - Do not ask the "resistance warriors" to water down their message.

No, with control of Congress and statehouses across the nation at stake, the liberal candidates who packed into a Washington hotel ballroom Thursday are convinced they will win in this fall's midterm elections only by embracing the passions and policies of the Democratic Party's far left flank.

"In this moment in American history, our job together is to stand up. It is to fight back," Vermont Sen. Bernie Sanders declared in an afternoon speech. He added, "The majority of the American people are on our side."

The message was cheered by an estimated 450 like-minded Democrats, most running in state and local elections this fall, who gathered for a four-day conference that offered a fresh window into intraparty tensions over how to capitalize on the surge in grassroots enthusiasm in the age of President Donald Trump.

"Any old blue just won't do," they chanted before Sanders took the stage, a knock on their party's centrists.

Earlier in the day, progressive strategist Joel Silberman shared this piece of advice for candidates appearing on television: "Dress like a conservative and talk like a socialist."

They are unapologetic supporters of policies like "Medicare for all," universal preschool, "debt-free" college and a $15-per-hour minimum wage. Animated by opposition to the Republican president, the self-described "resistance warriors" are aggressively fighting any calls to moderate their liberal passions.

Privately, at least, Democrats elsewhere are reluctant to embrace a midterm strategy aimed at the Democratic Party's most liberal voters, particularly when some of the most competitive races this fall will take place in regions Trump won two years ago.

Jesse Ferguson, a Democratic strategist who worked for Hillary Clinton's presidential campaign, suggested that tension within the party can be healthy.

"Competitive primaries help organize and help fuel the enthusiasm that'll help us take control," he said. "Candidates don't need to move all to the left or all to the centre. They need to come across as running for what they genuinely believe."

Republicans, meanwhile, encouraged Democratic efforts to celebrate their most liberal elements, certain that candidates who emulate progressive icons like Sanders and Massachusetts Sen. Elizabeth Warren will alienate moderate Democrats and disaffected Trump supporters who might otherwise back Democrats this fall or sit out the midterm elections altogether.

"It'll be tough to fight that winning message that Elizabeth Warren sends out to the world: socialism," said a sarcastic Doug Deason, a prominent Texas donor who is helping fund the GOP's midterm efforts. "That's great. That's what they should embrace."

They did just that at the liberal conference, which was designed to give lesser-known Democratic candidates at all levels a crash course on winning in the Trump era.

It's not enough to simply oppose the Republican president, said organizers, which included the Progressive Change Candidate Committee and the Sanders-backed group Our Revolution.

Participants were learning how to look good on television, find donors, design websites and, perhaps most importantly, develop a message around progressive economic priorities. The progressive movement's most aggressive allies were on hand: groups such as Indivisible, Planned Parenthood and the AFL-CIO.

Attendees represented at least 47 states, with the largest delegations coming from an assortment of red and blue states, including New Jersey, Texas, California, Florida, Massachusetts, Pennsylvania and New York.

Organizers report that 64 per cent of the candidates are running in districts Trump won in 2016. More than 80 per cent have never held office; 40 per cent are people of colour; 71 per cent are under the age of 44; and 20 per cent come from the LGBTQ community.

The Democratic Party will lose this fall if it doesn't embrace a broad slate of uncompromising progressive candidates who deliver "an Elizabeth Warren-style economic populist message," said Adam Green, co-founder of the Progressive Change Campaign Committee.

"Not only can you run on your values and win, but it is necessary to do so in some of these red districts," Green said.

News from © The Associated Press, 2018