Sen. Bernie Sanders (I-Vt.) addresses an audience during a March 31 rally in Boston. (Steven Senne/AP)

CHICAGO — One year after his Democratic presidential bid came to an end, Sen. Bernie Sanders (I-Vt.) will rally progressive activists Saturday night at the labor-sponsored People’s Summit, encouraging them to build a popular alternative to Republican policies.

“People have got to understand that we’re at a pivotal moment in American history, and it’s not clear which way we’ll go,” Sanders said in an interview. “There’s an enormous potential to improve peoples’ lives; on the other hand, there’s an opening for an austerity economy where everybody but the top 1 percent gets poorer. I will do my best to make people to understand that this is a 12-month-a-year operation, not about an election every four years.”

The summit is organized by National Nurses United, which spent millions of dollars to back the 2016 Sanders campaign and has since taken up a more prominent role in the political left. Our Revolution, the political group that Sanders spun off from his presidential bid, used the conference to hold meetings with labor unions; the Sanders Institute, launched by the senator’s wife Jane Sanders this week, co-sponsored hours of teach-ins about everything from money in politics to how to overcome movement infighting.

Sanders plans to tell activists that they were already scoring wins despite the Democratic Party’s national defeat, according to speech excerpts provided to The Washington Post.

“Ideas that, just a few years ago, seemed radical and unattainable are now part of Main Street discussion, and in fact, some of them are being implemented across the country as we speak,” Sanders will say. “Today, support for the concept of paid family and medical leave is gaining support. Today, states and communities throughout the country are moving forward to make public colleges and universities tuition free. Today, there is growing support for universal health care and in states like California and New York, we are seeing real legislative progress in the fight to pass a Medicare for All, single payer system.”

Sanders expressed less interest in a sentiment seen on T-shirts and unofficial swag throughout the McCormick Place convention center: a campaign to draft him again for president, either as a Democrat or as the leader of “a People’s Party.”

Asked twice about the draft efforts, Sanders pivoted to talk about the young voters who had come into his 2016 campaign and stuck around to work on left-wing causes. “I’m very appreciative of the support we have, but we’ve got to stay focused,” he said.