OMAHA, Nebraska >> Bernie Sanders, who attracted millions of college-aged and young adults to his presidential campaign last year, is following through on a promise he made when he left the race: to promote younger leaders for the Democratic Party.

It may not seem the most likely role for the slightly stooped, white-haired, 75-year-old Vermont senator. But Sanders rallied support Thursday for Omaha’s Democratic mayoral candidate Heath Mello, who’s half his age.

While the Democratic Party searches for a path back to power around the country, Sanders is using his popularity to draw thousands to events to promote next-generation Democrats, though his effectiveness so far is unclear. He’s on an eight-state circuit of rallies with Democratic National Committee leaders, visiting states Donald Trump carried in the November election.

“All over this country now, we’re seeing young people inspired to run,” Sanders told The Associated Press after headlining a rally of more than 3,000 in Omaha Thursday. “What all of this is about at the end of the day is the belief that, in order to preserve our democracy, we have to bring millions of people, in one form or another, into the political process.”

The 17 candidates Sanders’ political action committee has endorsed this year, including Mello, generally reflect Sanders’ call for newer faces in a variety of political positions and have a direct connection to urban concerns or social justice causes. Most are in their 30s or 40s.

“Maybe, just maybe it’s time to change one-party rule in Nebraska,” said in University of Nebraska-Omaha’s packed Baxter Arena Thursday, headlining a Democratic Party rally in the GOP-heavy state. “And we can start right here by electing Heath Mello as the next mayor.”

The contrast was apparent throughout the arena, where supporters waved signs featuring the familiar image of Sanders’ white hair and glasses alongside Mello’s jet black hair and sunglasses.

Mello, a 37-year-old state senator, exuded that youthful theme Thursday. “I just believe the City of Omaha needs a unifying, aspirational vision for the future,” he said.

Some of the candidates Sanders has endorsed are direct products of the his campaign, such as Khalid Kamau, who was elected to the South Fulton, Georgia, City Council on Tuesday. The 40-year-old Atlanta-area activist in the Black Lives Matter movement volunteered for Sanders’ campaign last year.

Others, such as Tom Pierrello of Virginia, reflect Sanders’ challenge to the party establishment. The 43-year-old former U.S. House member and adviser to former President Barack Obama is seeking the Democratic nomination for governor against Virginia Lieutenant Governor Ralph Northam.

But Sanders is using his popularity with younger Democrats to chiefly to inspire, rather than directly recruit, the younger faces he says the party needs.

It’s a tricky dance for Sanders, an independent who does call himself a Democrat — rather, a democratic socialist — but sought the 2016 Democratic presidential nomination and aligns with the party’s minority in the Senate.

Still, Sanders’ call for tax-supported free college tuition and, more broadly, his indictment of the political influence of the wealthy drew millions of younger voters to his cause during last year’s campaign.

In the primaries and caucuses he captured 70 percent of the 30-and-younger vote, and those 2 million votes far exceeded the combined totals for Democrat Hillary Clinton and Republican Donald Trump. Among Democratic primary voters alone, Sanders won a solid majority of support from voters ages 45 and younger.

Sanders seemed to pick up right where he left off when he ended his bid for the Democratic nomination less than a year ago. He brought many in the Omaha arena to their feet in rock-concert cheers when he reprised some familiar lines from his 2016 campaign.

“Health care is a human right, not a privilege,” Sanders shouted, his voice cracking.

In that way, most of what Sanders is offering on the DNC-sponsored tour through states Trump carried is the core of his standard campaign speech from last year.

After that campaign, he didn’t rule out a second bid for the White House, a prospect that troubles some next-generation Democrats. In four years, Sanders would be 79 — nine years older than Trump, who is the oldest ever to assume the White House.

But 19-year-old Corina Campbell of Omaha said she was ready to back Sanders for president again in 2020. “People might see their mistakes in not supporting him last time,” the community college student said.

It takes more than being a younger Democrat for a candidate to gain Sanders’ support. His political action committee decided against endorsing 30-year-old Georgia Democrat Jonathan Ossoff, a former congressional staffer who qualified Tuesday for a June 20 runoff House election after raising more than $8 million in mostly out-of-state contributions.

Sanders did endorse and campaign for 46-year-old Democrat James Thompson, a civil rights lawyer, ahead of his closer-than-expected losing effort in a special U.S. House election in Kansas last week. Thompson raised a fraction of Ossoff’s haul, and in smaller contributions, a hallmark of Sanders’ own campaign.

Some Democrats say Sanders is headed in the right direction, but must do more.

Rep. Tim Ryan, a Democrat from eastern Ohio, said the party needs to more aggressively organize its target audience — working- and middle-class voters who turned to Trump — and recruit from among them.

“We need newer faces across the board: veterans, police officers, teachers, coaches, firefighters that can improve our party’s brand at least visually,” said Ryan, who unsuccessfully challenged Nancy Pelosi for House minority leader late last year.

Such candidates, no matter their age, Ryan said, “can be powerful, as long as they are driving an economic message.”