Kamala Harris has a lot to do in a short time — build a team, choose a running mate, introduce herself to the country. But her most important task is to figure out what this election should be about.

Over the past week, Ms. Harris has been campaigning on protecting democracy, the rule of law and reproductive freedom from another four years of Donald Trump. As a forceful defender of abortion rights and a former prosecutor, she is ideally equipped to make these issues the centerpiece of her campaign. She relishes reminding voters of Mr. Trump’s status as a felon. “I took on perpetrators of all kinds,” she declared in her first campaign rally, at a gym in Milwaukee on Tuesday. “So hear me when I say: I know Donald Trump’s type.”

But standing up to Mr. Trump and defending reproductive rights is not enough. To defeat him, Ms. Harris needs to address the legitimate grievances he exploits — the sense among many Americans, especially those without a college degree, that their voices aren’t heard, that their work isn’t respected and that elites look down on them. She needs a message that reconnects the Democratic Party with the working-class voters it has alienated in recent decades. Delivering this message may not come naturally to her as a former senator from California, and Mr. Trump has wasted no time attempting to brand her a “radical-left lunatic.” But if she wants to shape a progressive politics that can wrest the future from the MAGA movement, then she has to try. It could be the difference between victory and defeat this November.

To begin addressing the anger and polarization gripping this country, Democrats need to recall what brought us to this volatile historical moment: An overwhelming majority of Americans — some 85 percent — believe that their leaders don’t care what they think and that they lack a meaningful say in shaping the forces that govern their lives.

This sense of disempowerment underlies the Republicans’ most potent issues in this campaign: inflation and immigration.

If Ms. Harris continues to repeat economic facts without acknowledging most voters’ feelings, she will fail to address the mood of discontent that has her running just behind Mr. Trump in the polls. Low unemployment, robust job growth, rising wages — by the usual metrics, the economy has been a success during the Biden years. And yet inflation looms so large for voters that most disapprove of the president’s handling of the economy. Why? Because inflation is not merely about the price of eggs. Many voters experience it as an assault on their agency, a daily marker of their powerlessness: No matter how hard I work or how much I make, I can’t get ahead or even keep up.