Joe Biden.

There is a wonderful progressive fantasy where we wake – woke, naturally – to discover Alexandria Ocasio-Cortez occupies the Oval Office.

America has rejoined the Paris accord, Bernie Sanders is secretary for renewable energy, Elizabeth Warren oversees an economy based on social justice, and Ilhan Omar is UN ambassador, speaking truth to power on a global stage. Donald Trump, convicted on multiple counts of obstructing justice, resides in a Colorado supermax jail, where the hue of his prison jumpsuit matches that of his hair.

This all may come to pass, but not yet. For now, Democrats have as their frontrunner for president Joe Biden, a 76-year-old white man, who is launching his third bid for the White House, driven by a strange, oil-water emulsion of arrogance and good intention.

“We are in the battle for the soul of this nation,” Biden said in a video message. “I believe history will look back on four years of this president and all he embraces as an aberrant moment in time. But if we give Donald Trump eight years in the White House, he will forever and fundamentally alter the character of this nation.”

The man Biden wants to take on quickly hit back, tweeting: “Welcome to the race Sleepy Joe. I only hope you have the intelligence, long in doubt, to wage a successful primary campaign.”

Many Biden admirers hoped he would sit this one out. Over the course of a long, if imperfect, career, he has emerged as someone who largely kept their dignity intact. In particular, his eight years as vice president to Barack Obama were judged favourably by almost everyone. Why risk that for a contest that will rapidly turn dirty, in which all your baggage and history – such as your support for a racist crime bill, your inappropriate touching of women, and your appalling questioning on Capitol Hill of an African American woman witness — will be intensely and repeatedly scrutinised? Hey, Joe, don’t you know when to quit?

Long before Biden delivered his announcement, he headed the list of likely Democratic candidates, with clear space between him and Sanders and even more space between Kamala Harris, Pete Buttigieg, Liz Warren and Beto O’Rourke.

Being the frontrunner has its advantages, but also its downsides. Mike Fraioli, a political strategist advising the 2020 campaign of Ohio congressman Tim Ryan, said whereas all the other candidates can move up, Biden – unless he scorches far ahead in a fashion similar to Trump in 2015 and 2016 – can only go down.

Biden will have to answer several difficult questions. Does he intend to be a one-term president? If not, how does he see himself coping with the demands of the job in his second term, when he is in his 80s?

Furthermore, for a party whose progressive wing is ascendant, whose most recent intake of House representatives contained more women and people of colour than other before, does the Democratic Party really want an elderly white man to be its face for 2020? The answer is that it might. The number one priority for Democrats now ought not to be ideological purity, or questions of gender or colour, but nominating someone who can defeat Trump.

Biden is not the only candidate capable of doing that. Harris, Warren, Sanders, Buttigieg and O’Rourke have all signalled that they’re ready for a fight. But he is certainly one of them.

He may not energise grassroots supporters, he may not excite supporters of the Green New Deal or universal healthcare. But as much as progressives might wish otherwise, America – especially large portions of that swathe in the middle – is for now a largely conservative place. In a two-party system, a successful candidate has to be as acceptable to as many voters as possible.

Biden might seem like yesterday’s man, but at this moment, he is the man many could vote for.