The 2024 Election Won’t Be Up To the Same Voters Who Chose Biden

The 2024 presidential election will be the first rematch in decades. But the US electorate that’s going to vote in November has changed more since 2020 than in the past two cycles for 41 states, including all seven considered battlegrounds.

States cumulatively welcomed more than 31 million eligible voters since Americans last voted for president, counting people who moved from a different state, turned 18, or became naturalized US citizens. That’s nearly one million more new potential voters than in the three years after the 2016 election, according to estimates from a Bloomberg News analysis of government and private data.

Though President Joe Biden won his first contest with presumptive GOP nominee Donald Trump in 2020, any number of factors could alter the outcome this year: Voter unhappiness over issues like inflation, abortion and immigration, third-party candidates who may draw votes from the two leaders and a shift in turnout.

But one largely overlooked factor is the changing makeup of the electorate, with some states swapping out nearly 15% of their voting-age population in 2020 through departures or deaths and replacing them with new eligible voters.

Migration between states is by far the biggest factor affecting the broader electorate. Naturalizations are a much smaller component but the fastest growing, followed by the number of people who’ve died in a graying America. Despite the pandemic’s seismic impact on the country, the Covid death toll has played a relatively small role in all the electorate turnover of the last few years.

When compared to the 2020 margin of victory, the number of new voters in the mix could be enough to change the balance in an election likely to be decided by razor-thin margins in just a handful of states, including in places like Nevada and Arizona.

“Most of the time there’s this focus just on the polls, how does this poll this year compare to that poll the year before, but what they don’t understand is there’s ongoing demographic shifts that are going on in those states that make some of those groups smaller and some of those groups way bigger,” said William Frey, a senior fellow at the Brookings Institution who studies the changing demographics of the electorate. “People for the most part disregard these kinds of changes that are going on.”

While less-populous states tended to see relatively more churn than bigger ones, the numbers are still significant in the Rust Belt battlegrounds of Michigan, Pennsylvania, and Wisconsin, which were among the least-changed nationwide. At least 10% of the voting-age population has switched out in the three states since Biden and Trump last faced off, representing an estimated 2.4 million new voters.

People moving between states tend to be younger and more diverse than the general population, said Frey, while younger White adults are more likely to be college-educated, shifting the balance away from a shrinking population of older White no-college voters.

“These are more ongoing developments, not developments that we have just noticed since 2022 or 2020. But these developments have political implications in swing states precisely because these states are decided by close margins,” said James Gimpel, a political geographer at the University of Maryland.

Educational attainment has emerged as one of the most powerful fault lines in US politics, as Trump builds a new Republican coalition upon a largely White, working-class base and Democrats increasingly win over those with a college degree. The ranks of the college-educated have grown over the past decades, but those gains slipped during the pandemic.

Also, some ethnic groups are growing faster than others, as birth rates for Black and Hispanic women outpace White women. Trump has made some limited inroads among minority groups, per recent polls.

In the states that matter most this time around, all this churn in the electorate is helping shift these demographic groups in meaningful ways. To be sure, voters don’t always cast their ballots in line with their peers, and can change their minds about candidates and issues over time.

“What we could be witnessing here is this tradeoff that the Republicans have made, and Trump in particular, to change the party coalition. It’s going to, counterintuitively for a lot of people, actually put more pressure on his campaign to register people than the Biden campaign,” said Michael McDonald, a political science professor at the University of Florida.

While several of these trends appear to favor Democrats, the latest Bloomberg News/Morning Consult poll reveals a stubbornly tight race, with Trump nosing ahead in most battlegrounds.

In all seven swing states, there are more newly registered voters than the margin of victory in the last presidential election, according to an analysis by Catalist, a voter-file firm that works exclusively with Democratic campaigns and progressive groups. Only about 70% of eligible voters are registered.

Ultimately sussing out the net effect of all these forces on who actually casts a ballot is difficult. Registration and turnout tend to be lower among recent arrivals, newly naturalized citizens and younger voters, so changes in the voting-age citizen population likely overstate changes in who votes on Election Day. Also, there are still more than five months until Election Day, and early registrants are normally wealthier, older and Whiter than the electorate as a whole.

But Catalist’s data can at least give us an idea of how this turnover is filtering through so far, with most states losing and replacing between 8% to 20% of their 2020 registered voters as of April.