But a significant difference this time around is that he will not be alone peddling his message of "revolution" and moving the party further toward liberal or progressive positions.
Four seasoned female Democratic senators — Elizabeth Warren of Massachusetts, Kamala Harris of California, Kirsten Gillibrand of New York and Amy Klobuchar of Minnesota — are already in the race vying for the same general constituency, along with several male hopefuls.
That fact might, however, work to Mr. Sanders' advantage in splitting the women's vote, which was not much of a factor in his own 2016 total. But the mushrooming #MeToo movement of women pushing back against sexual abuse and harassment has expanded that prospective pool of females at the polls.
The argument that the party needs a "fresh face," also used against former Vice President Joe Biden as he contemplates running again, likely will be heard more often regarding Mr. Sanders four years after his first try, despite his lively and energetic persona.
His self-identification as a democratic socialist will make him a ready target for President Donald Trump if he seeks re-election, given that Mr. Trump vows never to allow the United States to become "a socialist country."
Mr. Sanders in announcing his second presidential bid made clear he was eager to take on the president. Calling him "an embarrassment to our country," Mr. Sanders laid it on thickly: "I think he is a pathological liar ... a racist, a sexist, a homophobe, a xenophobe, somebody who is gaining cheap political points by trying to pick on minorities, often undocumented immigrants."
That tirade no doubt will be shared by the other Democratic contenders, who predictably will constitute a Greek chorus against the conservative flag-waving Trump base. It will be Mr. Sanders' challenge to survive erosion among his own faithful in the multi-candidate 2020 field.
In 2016, the Vermont senator benefited from considerable Democratic disenchantment with front-running former first lady Hillary Clinton, who nevertheless won nearly 3 million more popular votes than Mr. Trump in the general election. Next time around, it probably will be harder for Mr. Sanders to become the Democratic nominee, given so much competition and no longer being the sole serious alternative to Ms. Clinton.
At the same time, he demonstrated impressive residual support in disclosing he has already raised $6 million in 2020 campaign funds, along with his confident boast that much of his 2016 campaign organization remains in place for a second try.
Yet many of the liberal or progressive positions that won Mr. Sanders broad support then have several other declared Democratic contenders embracing them, including variations of Medicare for all, a $15 minimum wage and other favorites aimed at winning broad middle-class backing.
There is also the plain fact that the pre-election calendar has become much longer and more costly than nearly 60 years ago, when the sorting-out process began later and only a handful of states conducted primary elections.
In 1960, the eventual winner, Democrat John F. Kennedy, did not declare his presidential candidacy until the second day of January of that election year, and ran only in primaries in New Hampshire, West Virginia and Wisconsin in driving Hubert Humphrey of Minnesota from the race early.
A late and halting challenge from then Senate Majority Leader Lyndon Johnson of Texas, who ran in no primaries, fizzled and JFK was nominated on the first ballot at the Democratic convention in Los Angeles.
Next year, all the Democratic hopefuls will have to slog through a dozen or more delegate-selecting state primaries and caucuses after a year or more delegate-courting across the nation. It will be a trial for all of them, including Mr. Sanders, who then will be 78, as well as for by-then wearied voters.
But he remains a man driven by a vision to change not only the Democratic Party but also the country to the benefit of middle-class America, and he clearly has the grounds to claim a second try to continue that effort.
Jules Witcover is a syndicated columnist and former long-time writer for The Baltimore Sun. His latest book is "The American Vice Presidency: From Irrelevance to Power" (Smithsonian Books). His email is email@example.com.