It’s no secret that the political sentiments of Americans follow lines of race and ethnicity, education and age. But what makes presidential elections so competitive is how these demographic groups often balance each other out.

In 2024, this delicate equilibrium is key to understanding the seven battleground states where, according to the polls, the presidential race is closest. Last election, several of these states were decided by fewer than 40,000 votes. Since then, together they’ve added about 1.3 million potential voters, and the smallest shifts in sentiment or turnout among certain groups could be enough to alter the outcome of this election.

To better understand the demographic forces at play in the battlegrounds, The New York Times conducted a granular review of the 2020 contest and compared precinct-level results with census data to estimate who cast ballots and how they voted. We examined race and ethnicity, age, education and geography to identify trends and key groups in each state. (Gender is another growing factor in partisanship but was not part of this analysis.)

What to watch President Biden’s winning coalition relied heavily on Latino voters, who made up nearly a quarter of those who voted in 2020, a figure that will likely rise in this election. But while Latino voters in the state have typically favored Democrats, no group is a monolith.

Experts say Latinos have weaker party attachment than other nonwhite groups and could be persuaded to change their votes. Moreover, a significant share of this group is made up of U.S.-born, young Latinos who will vote for the first time, and their sentiment is less predictable. Recent surveys have shown former President Donald J. Trump making inroads with young people and voters of color.

Mr. Trump’s biggest support in 2020 came from white voters aged 35 and older. This group accounted for half of the ballots cast, due in part to the outsize number of white retirees in the state.

For Democrats, there are potentially more votes to gain. In 2020, there were more ballots cast for the Democratic Senate candidate than for Mr. Biden. “Those voters who voted for Mark Kelly but decided not to vote for Biden or Trump could have decided the outcome of the race,” said Samara Klara, a political science professor at the University of Arizona.

What to watch Democrats in Georgia have long been guided by the “30/30 rule,” a term made popular by the University of Georgia political scientist Charles S. Bullock III. It says that in order for Democrats to win, Black voters must make up 30 percent of all voters and at least 30 percent of white voters must vote Democratic.

Black voters, who cast nearly a third of the ballots in 2020, overwhelmingly favored Mr. Biden — by almost 90 percent. But that reliable base of support appeared to be slipping earlier this year, and it’s a group that experts say Vice President Kamala Harris must energize and excite. About 850,000 Black Georgia residents did not vote in 2020.

“If you have anemic turnout among Black voters, that will spell doom for the Democratic ticket,” said Andra Gillespie, a political science professor at Emory University.

Both parties will also be looking to appeal to a growing share of white voters with a bachelor’s degree, a group whose votes were split nearly evenly between Mr. Biden and Mr. Trump in 2020.

What to watch In 2020, Mr. Biden won Michigan handily — at least by the standards of a battleground state.

But Mr. Trump performed very well with white residents in suburban and rural communities, who made up nearly two-thirds of the voters in the 2020 election.

Democrats’ strong performance among nonwhite voters and in the suburbs of Detroit helped erase Republicans’ advantage in the suburbs around smaller cities in 2020. But even though Black voters overwhelmingly supported Mr. Biden, they were a relatively small group — just 14 percent of those who cast ballots. And experts say that Black support for Democrats could be waning in Michigan.

“There’s definitely an attitude that they aren’t represented, in comparison to their population and their outsize role in the Democratic party,” said Matt Grossmann, a political science professor at Michigan State University. He pointed to Detroit, a majority-Black city that does not have any Black representation in Congress. “The feeling is, how much attention are you paying to us? And how much are you taking us for granted?”

Disillusionment among the estimated 3 percent of Michigan voters who are Muslim and Arab American — a traditionally strong Democratic constituency — could also make a difference this year. Many of these voters have voiced their anger and frustration with the Biden administration’s support for Israel in the war in Gaza, and some have said they may choose to sit out this election or cast ballots in favor of a third-party candidate.

What to watch Nationally, education is a major political fault line, with college-educated voters far more likely to support the Democratic Party and less-educated voters favoring Republicans. But Nevada is the major exception to this rule: Democrats have won there in the past four elections, despite the state having a relatively low share of college-educated voters.

That’s because educational attainment divides mostly white voters, and many of Nevada’s less-educated voters are not white. Mr. Biden won half of the vote among voters without a four-year degree in Nevada, atypical for the nation as a whole.

Over the last several years, inflation has hurt working-class voters, and concerns about the economy could make it easier for the Trump campaign to eat into the Democratic advantage with blue-collar voters of color.

“Nevada is a little bit of a different animal,” said David Damore, a political science professor at the University of Nevada, Las Vegas, pointing to the state’s low voter turnout, high diversity and more transient population. “This all means that there are a lot of potential untapped voters that could be mobilized.”

What to watch In 2020, North Carolina gave Mr. Trump the narrowest lead of any state he won. Voters in rural areas, who accounted for nearly a fifth of the total, helped deliver Mr. Trump his victory.

But North Carolina also has many small cities with a strong partisan divide between city-dwellers, who favor Democrats, and suburbanites, who favor Republicans.

For Democrats to flip the state, they must lose fewer votes in rural areas and increase voter turnout in smaller cities, like Greensboro and Asheville, said Chris Cooper, a political science professor at Western Carolina University.

“If we see a marginal movement away from Trump in rural areas, that’s really important,” he said. “The map will still show these places as red, but those differences can be the difference between winning and losing.”

What to watch As it does in other states, education plays a big role in the partisan divide in Pennsylvania. White voters without a bachelor’s degree made up nearly half the total, and they favored Mr. Trump three to one in 2020. Even so, that wasn’t enough for him to overcome the coalition of white voters with a college degree and voters of color who delivered Mr. Biden a victory.

The other big factor is geography.

Mr. Trump dominated the state’s rural areas and small towns, as well as the Pittsburgh suburbs. But Mr. Biden had a strong showing in Pennsylvania’s cities and in the Philadelphia suburbs, areas that accounted for more than 40 percent of the votes in 2020.

Wisconsin saw a similar geographic divide among voters. The bulk of Mr. Trump’s support came from the state’s more than 1,000 small towns and the outer suburbs of Milwaukee.

But the fastest-growing part of the state is an area that increasingly favors Democrats: the suburbs of Madison, home to the main campus of the University of Wisconsin.

In 2020, turnout in Dane County, which includes Madison, was 89 percent.

“It is among the highest turnout counties in the country,” said Charles Franklin, the director of the Marquette Law School Poll. “The question for Democrats here is, is it even possible to squeeze more votes out of Dane County?”