Virginia Lt. Gov. Ralph Northam, left, and former Virginia congressman Tom Perriello. (Associated Press)

It has become a habit of journalism — one that was especially pronounced during the 2016 campaign — to write stories about how agonized voters are about choosing between candidates when they don’t like either of them. Far less common are stories about the difficulty voters can have in picking between candidates when they rather like them both.

Welcome to Tuesday’s Virginia Democratic primary for governor.

My strong hunch, based on the campaign itself and the polling I know about, is that Virginia Democrats will be happy to vote for either former congressman Tom Perriello or Lt. Gov. Ralph Northam in November’s general election. My other hunch, more subjective, is that many in the state are torn out of appreciation for different aspects of their respective candidacies.

Recently, the Post editorial board made a good case for Northam, arguing that his experience in state government and his temperament increased “his chances of success in the face of likely Republican control of one or both houses of the state legislature for the foreseeable future.” His reputation is that of a temperate, well-liked public servant who assembled broad support in his party before Perriello got into the race five months ago.

Democrat Lt. Gov. Ralph Northam, running to be his party's nominee for the Virginia governor race, says, "We can agree to disagree, but at the end of the day, I like to build consensus and again do what's in the best interests of Virginia." (Dalton Bennett/The Washington Post)

If Northam wins, I suspect he will owe part of his margin to two words in one television ad in which he describes President Trump as a “narcissistic maniac.” Northam won’t get any arguments on that from Democratic primary voters. And I challenge anyone outside Democratic ranks to try to make the case against Northam’s proposition.

The case for Perriello comes partly from the Bernie Sanders wing of the party: Democrats are better served running as full-throated progressives ready to take on the issues raised by economic inequality and the rigging of the political system by big money interests. Doing this will mobilize turnout, particularly among young progressive voters whom Democrats (and the anti-Trump cause more generally) need in the fall.

I would add a point in Perriello’s favor that for me is more personal than ideological: I got to know him in 2009 and 2010 because I was struck by and came to admire his independence and his willingness to blaze his own path in the early Obama years. An op-ed I wrote about Perriello’s campaign for reelection to Congress shows that long before the Sanders challenge, and long before the mainstream discussion caught on to the alienation of voters in the economically battered parts of the country, Perriello was trying to find a new set of policies and a new politics to respond to it. He was talking then about “demanding accountability from Wall Street and Washington.” He spoke of the need “to build, make and grow things in America,” warning: “We can’t win a race to the bottom with China.”

Democrat Tom Perriello, running to be his party's nominee for the Virginia governor race, says, "We need a bolder agenda that speaks more seriously to how much our economy has shifted." (Dalton Bennett/The Washington Post)

In order words, Perriello actually is the guy he says he is in this campaign, no small thing these days. I found his passion attractive then, and still do. He understood in 2010 what it took others six years to realize. And though Perriello lost in 2010, he did better relative to his 2008 showing than just about any other incumbent Democrat in a swing district. If all Democrats had held on to as much of their 2008 vote as Perriello did, they would probably have kept control of the House.

So that’s the choice voters will face. What’s bothersome in some of the commentary about Virginia is the subtext that links this primary to a broad struggle inside the progressive movement. As someone who believes in big-tent center-left politics, I worry about the bitter tone that often afflicts this internal argument. My reading of both the polls and the national temperament is that the center cannot win without the left — but also that the left cannot win without the center. It’s a matter of math, but also a matter of what the anti-Trump majority is looking for.

The Sanders wing is right that without the energy of progressives, particularly those under 30, Democrats cannot win. But there are many middle-of-the-road voters who despise what Trump is doing to our nation and are in search of ways to push back. They are looking for moderate progressives to form coalitions with them.

The elections in Europe in recent days offered intellectual fodder for both sides. The British Labour Party’s Jeremy Corbyn — who is, by the way, to the left of most Sanders supporters — showed how well a mobilizing strategy can work. He ran far better than anyone expected, partly because he was straightforward and unhedged about what he stood for. Alienated voters liked that. Nonetheless, he still did not put together a majority. In France, in the meantime, President Emmanuel Macron’s new centrist party (broadly similar in ideology to moderate Democrats in the United States) swept the first round of the country’s parliamentary elections. It seems headed to a big majority when voting is complete next weekend.

The center of gravity of an American progressive majority lies somewhere between Corbyn and Macron. That’s a lot of space, and there are substantive arguments to be had about where progressives should land, as Paul Waldman pointed out in an insightful piece on The Post’s Plum Line blog. But beware of a politics of heretic hunting in which the left attacks moderate or center-left politicians as sellouts and the moderates attack the left as naive radicals. Does anyone doubt that both wings would defend more aggressive steps toward universal health-insurance coverage and oppose new tax giveaways to the rich?

One could go on with a longer list, but the point is obvious, as Waldman also suggested: Both wings of the broad center-left agree that the country needs to move in a very different direction. In a democracy, politics is about addition, not subtraction. The kind of campaign Jon Ossoff is running in his Georgia special-election race for Congress is an example of how a candidate can win broad support in relatively inhospitable territory by acknowledging the breadth of the coalition he has to build.

So if Tuesday’s Virginia primary is a personal test of two thoughtful candidates, the real test will come Wednesday. The fact that whoever loses seems certain to support whoever wins suggests that progressives can have arguments and even primary fights without destroying their movement. This would be bad news for Trump.