Does Harris need a serious policy agenda? Only if she wants to win.

What kind of substantive campaign is Harris intending to run? Or does she really need substance at all?

That last question isn’t me being facetious. There’s a sentiment out there — probably a consensus view among leading Democrats, although I can’t say for sure — that Harris would be wise to resist offering any bold or detailed ideas for the country between now and Election Day.

For one thing, she’s not known to be a deep policy thinker, so it’s not likely Harris is going to develop a grand vision that would differentiate her from President Joe Biden (or any other Democrat) in a matter of weeks. And even if she did, there’s a fear that former president Donald Trump would turn that agenda against her, distorting the details just enough to make Harris seem like a deepfake Bernie Sanders.

When your opponent galvanizes your base just by existing, and when he has already failed to break the 50 percent mark in consecutive presidential elections, why hand him anything he can use? As a Democratic congressional aide put it to Politico this week: “Values unite and specific policies divide, so I don’t think there is a desire to spend the next 80 days litigating Medicare for All, for example.”

Harris will, as early as this week, offer up some pro forma policy agenda, which you can bet will be full of rhetorical marshmallows about building the middle class and expanding health care and all of that. (Her only specific proposal, to this point, was to shamelessly echo Trump’s call for an end to taxing workers’ tips.) But her main argument seems to be that she’s joyous and not Trump.

I can’t dismiss the merits of this approach out of hand. For 20 years or so, I’ve been making the case that elections are almost always won and lost on making people choose between competing arguments. (I even wrote a book to that effect, called “The Argument,” in case you run across it at an estate sale.)

But I’m open to the possibility that what drove our presidential elections in the 20th century just isn’t relevant anymore. Generations of Americans have now grown up in a world of vapid slogans — “Hope and Change,” “Make America Great Again,” etc. — where every election seems to turn on a handful of votes in a couple of states. Perhaps, in this new world, it’s better to let everyone project onto you whatever they want to see, rather than offer a more specific vision with which they might dare to disagree.

Maybe this notion that you should offer voters a cohesive, intellectual theory of the moment, the way Ronald Reagan or Bill Clinton did, is just something some of us reflexively cling to in our middle age, like fleece sweaters or Pearl Jam.

And yet, I can’t shake the discomfiting sense that we’ve seen this movie before, and we know how it ends. In 2004, John F. Kerry’s main agenda was that he wasn’t going to be George W. Bush. In 2012, Mitt Romney tried running as a cipher who wasn’t Barack Obama.

In 2016, you might remember, Hillary Clinton avoided any real argument other than that she wasn’t Trump, which she and her advisers considered a foolproof strategy. (And don’t howl at me that Trump had no argument of his own; “America First,” however warped in its worldview, served as the basis for all of Trump’s anti-immigrant, protectionist and isolationist policies.)

In every one of those campaigns, the candidate was thought to be, like Harris, a flawed communicator. Each became convinced that his or her least risky path to victory was to avoid lots of specific ideas or unscripted moments, to focus on making it to November without saying anything that would blow up the campaign.

In every case, it turned out to be a really good strategy for coming in second.

It’s true that substantive arguments are controversial and easily misconstrued. But it may also be true that nominees do better when they actually have to defend their convictions — and are more prepared to govern if they win.

Harris, of course, has less time to define herself than a typical nominee would. She might not be prepared to put forward an agenda of her own, and she might be persuaded by advisers that there’s too much risk in even trying to lay one out now.

She should at least consider the possibility that it’s riskier not to.