A recent presidential poll confirmed a hard truth for Virginia Democrats: Former vice president Joe Biden may be the only guy who can keep the commonwealth out of President Trump’s column in November.

That’s the takeaway from a recently released Mason-Dixon poll that shows the former vice president ahead of the president. The rest of the Democratic field achieves the seemingly impossible: Losing to an impeached Republican incumbent a year after Virginia Democrats won their first trifecta in a generation.

Naturally, this has upset the other contenders. Biden? You mean the 1988 Neil Kinnock knockoff? The 2008 wannabe who didn’t get past the Iowa caucuses. The 2020 front-runner who is carrying his son’s Ukrainian baggage?

We have to ignore all that history, plus things such as the poll’s margin of error (four percentage points), the pool of poll respondents (registered voters, not likely voters) and that the Iowa caucuses, Biden’s bête noir, are weeks away.

Fair enough. The data, however, confirm earlier polls showing Biden leading in Virginia.

Okay, fine. Let’s go with it. What do the numbers say?

Biden leads Trump 49-45 percent in Virginia. Not bad — not that much different from Hillary Clinton’s 49-44 percent victory over Trump in 2016 or Barack Obama’s Virginia victories in 2008 and 2012.

The good news for Democrats ends there.

Trump leads Sen. Bernie Sanders (I-Vt.) by 6 percentage points, Sen. Elizabeth Warren (D-Mass.) by 4 percentage points, and former South Bend, Ind., mayor Pete Buttigieg by a scant 2 percentage points.

All of this is can change. But don’t count on it changing much, because Biden has a few, very significant things working in his favor (in addition to endorsements from former governor Terry McAuliffe and Rep. Don McEachin).

The Mason-Dixon poll shows Biden leading Trump in two key constituencies: women and black voters. That isn’t surprising. Neither group is keen on Trump, and nothing will change that between now and Election Day, regardless of whom Democrats nominate.

But black voters are the foundation of Biden’s support — in Virginia and elsewhere. We’ve seen just how influential this group of voters can be in Democratic primaries, and why there’s real reason to believe Biden is stronger not just in the primary but the general election, too.

In 2016, Clinton’s overwhelming support from black voters on Super Tuesday swamped Sanders.

In the Virginia primary, alone, Clinton won 84 percent of the black vote, which helped propel her to an easy 64-35 percent win over Sanders.

Women and black people stuck by Clinton in the general, where she won 56 percent of the women’s vote and a whopping 88 percent of the black vote (and 91 percent among black women).

Clinton needed every one of those votes to win Virginia in 2016, just as Obama did in 2012 and 2008.

The political calculus is no different for Biden in 2020.

As the Associated Press’s Errin Haines reported, those who’ve known Biden the longest “speak to the depth of good will he has among black voters.”

Biden has spent a lifetime campaigning among and advocating for black voters. He’s also got that eight-year stint as Obama’s VP. Haines found that Biden’s service to Obama matters — a lot.

McEachin referenced it in his endorsement, saying Biden was “a staunch and steadfast partner to President Obama during his historic presidency.”

The Mason-Dixon poll may not be perfect, and there’s ample time for everything to change. But the numbers tend to reinforce the idea that, despite many, many caveats, Biden really might be the only Democrat who can defeat Trump in Virginia.

Put another way: If Democrats nominate anyone other than Biden, then Virginia becomes a swing state again.