Sure, Democratic US presidential hopefuls are already herding into the starting gates, staking out “lanes” of potential support among the party’s progressive/centrist/suburban female/millennial/etc tribes.

It’s fun to watch, and so far illuminating, with candidates tossing out serious policy issues – universal health care, radical tax overhauls – and testing campaign personas to see how they fit.

But it still feels like baseball’s spring training, the pre-season weeks in the US sunbelt where players shake off winter and get in shape for Opening Day. And in the 2020 presidential season, that day won’t come until former vice president Joe Biden announces whether he’s in the race to unseat President Donald Trump.

On Monday, Mr Biden teased that he was “a lot closer” to deciding than he was at Christmas, and would make a decision “soon”. The political chatterati seem to think he’s jumping in, though Mr Biden’s cautious language (“I’m making a decision now whether or not I’m the right person”) still gives him room to bail out.

The Go Joe/No Joe camps have equally compelling arguments. Go Joers say only Mr Biden has the common touch and middle-class empathy to win back disaffected white midwestern voters lured to Mr Trump in 2016. No Joers say he’s too old, too accommodating, too associated with the desiccated centrist wing of the party that squandered everything last time around.

Both theories betray a distrust of the voter, and of the refreshingly Darwinist wisdom of the campaign trail.

Some experts say Joe Biden is the Democrats’ best hope at defeating Trump. Photos: Getty

Whatever you think of Mr Trump, he spent 15 months running for president – his every racist, ignorant, corrupt instinct on ample display during the long race. If some voters were duped, they chose to be or didn’t care. That Hillary Clinton could not defeat him says more about her failures than his deceit.

If Mr Biden declares, the “go” and “no” theories will be road-tested. He will have to articulate his positions, defend his policy proposals, explain his decades of Senate votes. If he’s adept, his arguments will become more cogent and persuasive. If he’s not, his average guy backslapping will be seen as insufficient to the task of defeating the president.

Democrats are openly desperate to beat Mr Trump. For months, they’ve been debating about whether electability is better than bold policy. It’s a good story, and the press is understandably pitting “centrists” against “progressives” ie: Mr Biden against, say, Elizabeth Warren. It’s a soul-of-the-party drama that will go on for months.

But voters have a way of shaking off those labels. A recent poll of Republicans, for example, showed 45 per cent favoured a 70 per cent tax – yes, 70 per cent – on incomes above $10 million. Why? Because it seems reasonable and fair.

That it doesn’t adhere to accepted conservative catechism just shows that ordinary people don’t live by dogma. They live real lives and are looking for practical solutions. Heck, 10 years ago, no one would have believed same-sex marriage could be as politically unremarkable as it has become.

Mr Trump’s 2016 run may have ended forever the tradition of overly cautious, careful campaigning. This year already, Democratic candidates like Kamala Harris and Ms Warren are making bold policy proposals, testing them among voters while burnishing their stump styles. This is their spring training, their practice season.

My hunch is the debate between electability and progressive policy will become less binary as the campaign rolls on. Policies like taxation and immigration will be viewed on their own merits, not on their liturgical purity.

Depending on the candidate, one’s campaign positions may not all fit neatly into either progressive or centrist camps. A la carte may prove more attractive than all-you-can-please.

So I say Go, Joe, and stop the waiting game. Articulate why you think you’re the best person for the job. Challenge others to challenge you. But know that others in the Democratic Party have already been on the practice field, and are looking to replace you in the line-up.

If you’re serious, get off the bench and see if you’ve still got what it takes. The American voters will be better for it.