CHICAGO (Reuters) - Buoyed by the British Labour Party election gains this week, Vermont Sen. Bernie Sanders on Saturday urged a summit of progressive activists who propelled his presidential candidacy to ramp up efforts to win elections and help remake a Democratic Party he deemed a failure.

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“They won those seats by standing up to the ruling class,” he said, referring to the British elections and citing wins by progressive U.S. candidates in several state and local races while writing off losses as evidence liberal progressives could still be competitive even in conservative states.

But Sanders, who lost the Democratic nomination nearly a year ago to Hillary Clinton, showed little interest in a push by “Draft Bernie” activists who want him to start his own “People’s Party.” Many activists blame establishment Democrats for losing to President Donald Trump by failing to embrace a more populist left-leaning agenda.

Sanders headlined the three-day “People’s Summit” in Chicago, attended by celebrity activists including actors Danny Glover and John Cusack, which brought together main progressive groups such as National Nurses United, Democratic Socialists of America and People for Bernie.

Many activists said they hoped to transform the momentum from recent protests such as January’s Women’s March in Washington into concrete plans to support a growing wave of grassroots candidates to secure electoral power.

“We could have 10,000 people marching, but if we don’t have some means of translating that into winning political office and enacting a legislative progressive agenda, at the end of the day, what does it amount to?” said Nick Brana, the former staffer for the Sanders campaign leading the “Draft Bernie” group.

With Trump mired in controversy over incidents such as the firing of former FBI Director James Comey, and Democrats having lost ground in statehouses and in Congress, RoseAnn Demoro, head of the nurses union, said the movement Sanders began was at a “tipping point” of broadening its support.

Leaders with the Democratic Socialists of America said their membership has bloomed from 6,000 before the election to 22,000.

Others warned that progressives don’t have the fundraising firepower they need or that gains were still fledgling.

“We’re closer but we’re not yet winning,” said activist and writer Naomi Klein.

Still, Sanders credited progressives with increasing public acceptance of proposals such as a $15 minimum wage, renegotiating trade policies and offering free college tuition. He got a standing ovation when he said the California Senate recently passed a single-payer health care plan.