Thousands of people packed a Bernie Sanders rally in San Francisco’s Fort Mason on a sunny Sunday afternoon as the independent senator from Vermont continued his campaign for U.S. president as a Democrat with a fiery populist speech, vowing to turn his progressive agenda into reality.

The crowd cheered and chanted “Bernie, Bernie” as Sanders laid out policies that he said were rejected as “radical and extreme” in his 2016 presidential quest, but have now found widespread support.

“The ideas we were talking about, the media and everyone else said they were so far out and so crazy, nobody in America supports them,” he said, enumerating concepts like raising the minimum wage, combatting climate change, reforming the criminal justice system and the immigration system, legalizing marijuana, guaranteeing health care to all, making college free, and removing the influence of the rich and super PACs in elections.

“Today Democratic candidates from school board to president are talking about exactly these same issues,” said Sanders, with the Golden Gate Bridge towering behind him as U.S. and California flags fluttered in the breeze.

Indeed, in 2016, Sanders was the only candidate promoting a single-payer health care plan and proposing that college tuition be free. Now, several of his new competitors are staking out similar positions. Democratic Sens. Elizabeth Warren of Massachusetts, Kamala Harris of California and Kirsten Gillibrand of New York, among others, support Medicare for all. Harris is among those who back free public college education.

Sanders took the stage minutes after Attorney General William Barr released a summary of Special Counsel Robert Mueller’s probe of Russian interference in the 2016 election.

“I have something in my email box, I’ll read it right after this,” Sanders said. “I know it is a summary of the report. Well, I don’t want a summary of the report. I want the whole damn report because nobody, especially this president, is above the law.”

That remark drew cheers and applause, as did his other digs at President Trump, “the most dangerous, dishonest president in American history,” Sanders said.

While the enthusiastic crowd was packed with people waving Bernie signs, wearing Bernie T-shirts and buttons, and even sporting body paint endorsements, not everyone was committed to him. Several said they are still weighing other Democratic candidates, with Warren and Harris referenced most frequently.

“I want to hear what they (candidates) have to say about college being free for all, the student-loan debt crisis and health care reforms, especially pharmaceutics pricing,” said Yemi Bankole, 25, a health care administrator from Oakland.

“He’s an intelligent adult; a rare thing in U.S. politics,” said Steven Gray of San Francisco. “His donations are based on ordinary people, not corporations.”

Sanders was in San Francisco as part of a West Coast campaign swing that took him through San Diego and Los Angeles.

He faces tough odds to match his surprising 2016 performance in California, where Hillary Clinton beat him with 53 percent of the vote to his 46 percent and she won all of the state’s major cities. His California performance will matter more this time around, because the state has moved up its primary to March 3.

While Sanders won 2.3 million votes in California in essentially a one-on-one matchup against Clinton, now he is one in a field of 15 candidates (and counting), including Harris, who has locked up endorsements from top lawmakers across the state, including Gov. Gavin Newsom.

Then, he could position himself as an underdog taking on Clinton, the establishment candidate who had vastly more name recognition, money and a network of donors and supporters across the country.

But now, at least pending former Vice President Joe Biden’s expected entry in the race, Sanders is the front-runner, complete with a 50-state network of small donors and supporters. He said he raised more than $5.9 million in the first 24 hours after he announced his candidacy in February, tops in the self-reporting field until former Rep. Beto O’Rourke of Texas claimed a $6.1 million first-day haul this month.

Sanders, who has long been reluctant to weave much of his personal life into his political life, is now loosening up on that front, too. As he did Sunday, he frequently peppers speeches with how his lower-middle-class upbringing in Brooklyn shaped the policies he has long championed. “I came from a family that lived paycheck to paycheck,” he said.

Sanders’ 70-minute speech Sunday included humor, some of it self-deprecating.

He may not be a math genius, he said in conclusion. “But this I know: They are the 1 percent. We are 99 percent. If we stand together, we can create a country that will be the envy of the world.”

Carolyn Said and Joe Garofoli are staff writers. Email: csaid@sfchronicle.com, jgarofoli@sfchronicle.com Twitter: @csaid, @joegarofoli