The UK election proved what the American left has been saying for years

CHICAGO — At the People's Summit, a who's who gathering of the American left, there's an electric energy in the air. As progressive celebrities rub shoulders with union organizers, one subject ubiquitously elicits a coy smile and a sense of desperate hope from those on the floor of the convention: the British election.

Thursday’s historic election in the United Kingdom is being heralded across the British Isle as a victory for the Labour party and the unapologetically leftist agenda of Labour leader Jeremy Corbyn. But almost 4,000 miles away those election results are being celebrated by mass gathering of America’s political left.

"What we saw yesterday was that left can win, and the center often doesn’t," Winnie Wong, cofounder of the group People for Bernie said in an interview in Chicago on Friday.

The day after the U.K. election, Wong stood in the middle of a crowded convention center in Chicago surrounded by thousands of excited progressive activists she helped bring to the city.

For the past year, America's most prominent leftists have been pushing Democrats on a single message: Push an unapologetic leftist platform, with policies like single payer healthcare and free college tuition, and young people will show up like never before to beat back the conservative establishment. And now, in their eyes, the British people have proven their point.

The summit is happening amidst a battle for the soul of the Democratic Party. Even after the 2016 primary, there is a hard divide between those who want the Democrats to support popular policies like single payer healthcare, and the party establishment that wants to rope in center-right voters and the ever-elusive moderates who might be turned off by Trump.

"There’s a voting coalition in America that Sanders helped reveal of working class people, young people and independents," Waleed Shahid, a cofounder of #AllOfUs, a grassroots group working to push the Democratic Party to support more progressive candidates, said in an interview at the People's Summit. "If it can be expanded to include more voters of color, it could be a winning party for America. We need to make that coalition possible instead of talking to Romney voters."

Young voters are an essential part of building that coalition, organizers say, because millennials and Gen Z are far more progressive than generations before. Americans under 30 cast more votes in the primaries for Bernie Sanders than Hillary Clinton and Donald Trump combined, and are bigger fans of socialism than capitalism.

"One thing driving Labour’s over performance was youth turnouts," Sean McElwee, a policy analyst who studies voter attitudes and behavior at the progressive think tank Demos, said in an interview.

McElwee thinks that Labour’s success could be a model for progressives in the United States provided they learn some key lessons about how to enlist and galvanize voters.

"[In 2016] Clinton had a fine policy platform, but the difference is the messaging," McElwee said. "The future of Democrats is an aggressive, progressive policy platform combined with populist messaging."

But McElwee points out that just capturing the youth’s imagination isn’t enough — you have to get them registered to vote. An essential key to Labour’s victory was that voter registration increased by 20% over the 2015 elections, delivering an enormous student vote for the Labour Party.

"When you reduce the barrier to registration, you’re going to increase turnout," he said. If every registered voter under 30 in the U.S. voted, their turnout would still be lower than that for voters over 65. We solve that with pre-registration. When you go to the DMV, you should have the opportunity to register there so you’re on the rolls at 18."

Over the weekend, the People's Summit will hold political education workshops, and draw together union organizers, activists, would-be congresspeople to build a united front that can change the face of the Democratic Party. The conference puts and emphasis on tools — the skills and networks needed to get the Democrats to swing left.

The U.K. has given them a new tool in their belt: the ability to say, in the face of anyone who doubt the electability of a leftist, "Look what happened to Jeremy Corbyn."

Andrew Joyce, politics writer for Mic, contributed to the reporting of this story.