Spoiler alert: Bernie Sanders, who last week became Hillary Clinton's first declared challenger, will not beat her to next year's Democrat presidential nomination.

But that does not make his quixotic campaign any less interesting: Mr Sanders is the first Jew to run for president since Senator Joe Lieberman's ill-fated bid in 2004.

In many ways, Mr Lieberman - who, as Al Gore's running mate in 2000, was the first Jewish candidate on a major party ticket - is Mr Sanders's polar opposite. While Mr Lieberman drifted steadily to the right - he campaigned for Republican John McCain in 2008 - the Vermont senator is a self-described socialist.

The longest-serving independent in the history of the US Congress, Mr Sanders was elected the north-eastern liberal state's sole member of the House of Representatives in 1990 and became one of its two senators in 2006. Known throughout the state simply by his first name, he has regularly won the backing of around two in three Vermonters, winning re-election in 2012 with 71 per cent of the vote.

Seventy-three-year-old Mr Sanders's campaign will, however, represent the last hurrah for a generation of left-wing Jewish activists who, as he did, marched for civil rights and against the Vietnam war. Unusually, Mr Sanders has ended up wielding a degree of political power without - seemingly - compromising those principles. He got his break when he was narrowly elected mayor of Vermont's largest city, Burlington, in 1981. Mr Sanders's support for left-wing causes led it to be dubbed the People's Republic of Burlington, but his sound stewardship finally led the state's voters to take him seriously.

Will Democrat primary voters do likewise next spring? Certainly, his dovish foreign policy instincts - he voted against the Iraq war, has called for Saudi Arabia, not America, to lead the fight against Islamic State, backs Barack Obama's nuclear deal with Iran and boycotted Benjamin Netanyahu's recent address to the US Congress - will appeal to the party's grassroots. So, too, will his attacks on the "billionaire class" and big money in politics, and his promise to put the "obscene levels" of inequality in America at the heart of his campaign.

However, Mrs Clinton's chummy tweet welcoming him to the campaign indicates she knows she has little to fear from Mr Sanders. The frontrunner will have calculated that - so long as it does not come in the form of popular Massachusetts senator Elizabeth Warren - a multitude of challengers to her left will splinter the opposition, allowing her to maintain a general election-winning centrist stance during the primaries.

As for Mr Sanders, while he spars with the likely next president of the United States and her rivals this autumn, he may reflect that it has been quite a journey for the son of a struggling paint salesman whose family perished in the Holocaust.