HORSHAM, Pa. >> Just days before what might be the only debate between Vice President Kamala Harris and former president Donald Trump, business leaders and local officials here at the Eastern Montgomery County Chamber of Commerce luncheon were not eager to talk about the choice before the country.

They gathered on a sunny Thursday afternoon to hear from their Democratic member of Congress, Rep. Madeleine Dean. Both she and her audience were resolutely focused on the practical and immediate: what the federal government could do to lift the area’s small businesses and nonprofits and support its local governments.

It is a mark of the deep divisions among the state’s voters that most stewards of the region’s private sector would only talk about their views on the election if they wouldn’t be quoted by name. Several explained that no local store, restaurant or bank wanted to offend parts of a customer base passionately split on who should be the next president.

The coming face-to-face battle between Harris and Trump did not even come up in the Q&A until I raised it at the end of Dean’s remarks. Her answer, which didn’t mention either candidate by name, was at once diplomatic and pointed.

“I’ll be paying attention to their words, the truthfulness of it,” said the congresswoman, who represents most of Pennsylvania’s Montgomery County in the Philadelphia suburbs, along with parts of Berks County near Reading. “Is it factual? Based on what you all care about? What we care about, what our families care about? Or is it demeaning? Is it othering? Is it filled with hatred or bigotry? I’ll be looking for the bright and the light and the love.”

She didn’t even have to say “Vote for Harris,” and her statement reflected something important about presidential debates. While the panel of journalists moderating Tuesday’s event will and should ask about specific issues, the relatively small number of voters who are still undecided or might be open to switching are far likelier to judge Harris and Trump on their affect, coherence, empathy and toughness.

“In a presidential debate,” said Geoff Garin, a Harris campaign pollster, “it’s very hard to separate the messenger from the message.” Especially in a contest involving Trump.

Of all the states in play, Pennsylvania (with 19 electoral votes) is the most important and one of the most closely divided. As Democratic Rep. Brendan Boyle of Philadelphia told me, “We seem almost destined to be a one-point race.” The state is also the clearest illustration of how the candidates must keep a complicated simultaneous equation in mind as they speak on Tuesday.

Harris needs to run up strong margins in the once-Republican suburbs of Philadelphia that were key to Joe Biden’s victory in the state four years ago. Montgomery County, for example, gave Republican George H.W. Bush 60 percent of its vote in 1988, but 59 percent to Hillary Clinton in 2016 and 63 percent to Biden in 2020. Harris must hold or grow Biden’s share.

At the same time, Biden’s margin in Philadelphia was slightly behind Clinton’s, and Garin said Harris’s campaign is focused on turning out a larger vote there, capitalizing on the new energy she has inspired among Black and young voters. But the issues and appeals that work for such voters - there, and also in Pittsburgh - are not the same as those that will draw out older suburban moderates.

Finally, Harris must shave Trump’s margins among White working-class voters and improve Democrats’ share among working-class Latinos, particularly in Pennsylvania’s old industrial areas such as Erie, Scranton, Wilkes-Barre and Allentown. Even if Harris wins the state, most of its 67 counties, many of them small and rural, will vote for Trump.

“The trick for Harris,” said former governor Ed Rendell in an interview, “is to improve by two to three points in all these counties.” To win that share, he said, Harris’s should stress her conversion to supporting fracking, Trump’s broken promises to invest in infrastructure and bring back coal and manufacturing jobs, and his offensive comments about veterans. (Pennsylvania ranks fourth among all states in its population of veterans.)

Pennsylvania illustrates how the challenge of debates is to keep the particular and the general in mind at the same time. While the issues Rendell mentioned - along with overriding concerns about economics, reproductive rights, immigration and gun safety - will be important, Dean is right about what will determine the larger outcome of Tuesday’s encounter. Voters will decide who is more appealing based on gut judgments: whom they are comfortable with, whom they trust most.

One of Harris’s central jobs will be to persuade Republicans and conservative-leaning independents who voted for Trump but are exhausted that she is a safe alternative. Boyle sees her doing this by being “eloquent and thoughtful” - but above all, by being “normal.” In the normality contest, he expects Trump to give her a lot of help.