Once the general election campaign really starts, the dynamics change from what we saw on the debate stage. And there the issues still favor Mr. Trump. Ms. Warren’s government monopoly on health care is a tough sell. She was right to say that she has never met anyone who loves their health insurance company, but not many people who have health insurance want to get rid of it. Gun control is very popular with the Democratic base, but much less so in western Pennsylvania and rural Michigan and Wisconsin, where this election may be decided. Likewise with the Green New Deal, reparations and the whole progressive social justice agenda.

If Mr. Biden falters, though — and maybe even if he doesn’t — Ms. Warren is a strong, viable candidate who, in some ways, might be more effective against Mr. Trump simply because she can articulate the challenges of the middle and working classes that are the source of his political power. She was at her strongest when she was telling her own life story. She came from modest means and went to the University of Houston for $50 per semester as a nonresident. It’s $13,000 to $15,000 for nonresidents now. Then she went to law school while her aunt helped care for her two small children. She got ahead in the way that many Americans want their children to get ahead but see as less and less possible.

It’s a powerful narrative because it describes an America with a large, self-confident, self-sustaining middle class. Today, much of that is gone, and what’s left is under pressure. This is the same sense of decline that Mr. Trump tapped into. It’s powerful because it’s real. This is where the narrative of blue-collar, lunch-bucket Joe Biden feels less authentic and less relevant than Elizabeth Warren, the special ed teacher turned law professor.

When it came to the other candidates, I couldn’t shake the sense that they were role-playing the version of themselves they had read about in a friendly profile of their campaign or that came in a briefing book. Beto O’Rourke and Julián Castro both played their parts perfectly, genuflecting to the gods of multiculturalism by speaking Spanish during the debate. Andrew Yang told us, “I am Asian, so I know a lot of doctors” and pushed a $12,000-per-year sweepstakes for 10 lucky families because he’s the rich novelty candidate from Silicon Valley. The only thing that would have been more in character is if he had said the payments would be made in Bitcoin.

Among the other candidates, Cory Booker wound us up with another anecdote about some person he met as soon as he moved to Newark, while Pete Buttigieg tried to maintain the imperial, aloof self-confidence of the Rhodes scholar who became the mayor of a small Midwestern city and defies stereotypes. It all seemed too packaged, too planned, too in character. Slick, consultant-driven, focus-group-tested, too-perfect candidates seem less believable these days when the best candidates let loose on social media and connect directly with voters.

But the question on which all of this turns remains the same: How do these candidates and these issues play in the handful of states that will decide the election? Arizona and other Democratic dream states probably remain out of reach. But in the upper Midwest the election will again turn on issues of economic security and American identity. Rust Belt voters have seen their communities decimated first by deindustrialization and the exportation of their jobs and are now dealing with the fallout in the form of opiate addiction, alcohol abuse and increased suicide rates.

They are looking for a president with a plan not just to alleviate their immediate economic need with a handout, but to rebuild the country’s economy in a way that encourages the growth and security of the middle class and restores a sense of confidence in the American nation. Elizabeth Warren is interesting because she correctly identifies many of the challenges facing the broad middle class, but this is still ground that favors Mr. Trump if he returns to the issues that worked in 2016.

The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.

Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram.