In theory, a wide array of Democrats from across the country appear to be eager to take on Donald Trump in 2020.

They seem to think that he’ll be easy to defeat for re-election, just as Hillary Clinton probably thought she’d crush him in 2016. That has a number of Democrats criss-crossing the country before the midterm elections, trying to boost their national profile. They include U.S. Sens. Elizabeth Warren of Massachusetts, Bernie Sanders of Vermont, Cory Booker of New Jersey, and Kamala Harris of California, among others.

Though this seems like a diverse group of candidates — some are from the West Coast, some the East Coast; some are women; some are minorities — in practice they’re not entirely dissimilar. They largely fit the same mold: aside from Bernie Sanders, they’re recent arrivals on Capitol Hill who firmly lie on the left side of the political spectrum, to varying subtle degrees. There’s not a single governor in the group yet, nor is there anyone from the Midwest or the South.

These candidates and their supporters appear to be hoping that they can simply activate the Democratic base’s deeply ingrained dislike of Trump and coast to victory.

If they’re operating under that theory, then it makes sense that they’re looking for not necessarily the most electable Democrat, but the most electable progressive. They hope to take the opportunity to elect the most liberal president since Lyndon Johnson, operating under the assumption that any Democrat will be able to win.

It’s easy to see why liberals are thinking of 2020 in these terms. Trump does have low approval ratings, after all, and he did face an unpopular opponent two years ago in Hillary Clinton.

This is a faulty understanding of the 2016 presidential election, however. All over the country, voters didn’t just vote against Clinton — many of them voted for Donald Trump. While there were many moderates and independents who may have only reluctantly voted for Trump, there were also voters who turned to him after twice voting for Barack Obama. These voters weren’t racist, nor were they conservatives willing to vote for Trump in exchange for a few judges.

These are the voters Democrats have to win back if they want to be competitive in 2020.

They won’t be able to do that simply by nominating a dyed-in-the-wool liberal who runs around shouting “Resist!” all the time. These voters may not be thrilled with everything Donald Trump’s done and said, but neither are they ready to man the barricades for Generic Democrat. They need to be convinced. That likely won’t be done by a Democratic senator they’ve never heard of from a solidly Democratic state.

No, what they need instead is an already-established, well-known Democrat who is able to convince them that he understands their problems and can fight for them.

They may have just such a figure in former Vice President Joe Biden, who considered running in 2016 but ultimately decided not to after the untimely death of his son Beau.

Biden recently confirmed that he is thinking about running for president in 2020, prompting Trump to say that running against him would be a dream. Trump should be careful — that dream could well become a nightmare if it turns into fruition.

Uniquely amongst the many potential candidates, Biden has the capability to unite the disparate parts of the Democratic Party. For Democrats who loved Obama but were less enthralled with Clinton, and didn’t even warm up to her after the primaries, he represents a distinct connection to the previous administration. As such, he can take credit for many of their successes and bask in the affection for Obama in a way few other candidates can. It will also make it hard for his primary opponents to question his progressive credentials, as they so readily did with Clinton.

At the same time, his political base has always been white working class voters — exactly the demographic who abandoned Clinton to send Trump to the White House.

To be sure, nominating Biden alone will not be enough to bring these voters back to the Democratic Party, but it’s a start. Biden may decide not to run, but Republicans shouldn’t immediately dismiss him. He’s certainly an excellent campaigner, with a proven ability to connect to voters on a personal level that could prove formidable in the fall — and the perfect antidote to Donald Trump for the Democrats.

Jim Fossel, a conservative activist from Gardiner, worked for Sen. Susan Collins. He can be contacted at: jwfossel@gmail.com