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President Joe Biden won a decisive Electoral College victory in 2020 by restoring old Democratic advantages in the Rust Belt while establishing new beachheads in the Sun Belt.

But this year, his position in polls has weakened on both fronts. The result is that, even this far from Election Day, signs are developing that Biden could face a last-mile problem in the Electoral College.

Even a modest recovery in Bidens current support could put him in position to win states worth 255 Electoral College votes, strategists in both parties agree. His problem is that every option for capturing the final 15 Electoral College votes he would need to reach a winning majority of 270 looks significantly more difficult.

At this point, former President Donald Trumps gains have provided him with more plausible alternatives to cross the last mile to 270. Trumps personal vulnerabilities, Bidens edge in building a campaign organization, and abortion rights prominence in several key swing states could erase that advantage. But for now, Biden looks to have less margin for error than the former president.

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Bidens odds may particularly diminish if he cannot hold all three of the former blue wall states across the Rust Belt that he recaptured in 2020 after Trump had taken them four years earlier: Michigan, Pennsylvania, and Wisconsin. Biden is running more competitively in Pennsylvania and Wisconsin than in any other swing states. But in Michigan, Biden has struggled in most polls, whipsawed by defections among multiple groups Democrats rely on, including Arab Americans, auto workers, young people, and Black Americans.

As James Carville, the veteran Democratic strategist told me, if Biden can recover to win Michigan along with Pennsylvania and Wisconsin, you are not going to lose. But, Carville added, if Biden cant hold all three, you are going to have to catch an inside straight to win.

For both campaigns, the math of the next Electoral College map starts with the results from the last campaign. In 2020, Biden won 25 states, the District of Columbia and a congressional district centered on Omaha, in Nebraskaone of the two states that awards some of its Electoral College votes by district. Last time, Trump won 25 states and a rural congressional district in Maine, the other state that awards some of its electors by district.

The places Biden won are worth 303 Electoral College votes in 2024; Trumps places are worth 235. Bidens advantage disappears, though, when looking at the states that appear to be securely in each sides grip.

Of the 25 states Trump won, North Carolina was the only one he carried by less than three percentage points; Florida was the only other state Trump won by less than four points.

Its not clear that Biden can truly threaten Trump in either state. Bidens campaign, stressing criticism of Floridas six-week abortion ban that went into effect today, has signaled some interest in contesting the state. But amid all the signs of Floridas rightward drift in recent years, few operatives in either party believe the Biden campaign will undertake the enormous investment required to fully compete there.

Bidens team has committed to a serious push in North Carolina. There, he could be helped by a gubernatorial race that pits Democratic Attorney General Josh Stein against Republican Lieutenant Governor Mark Robinson, a social conservative who has described LGBTQ people as filth and spoken favorably about the era when women could not vote. Democrats also believe that Biden can harvest discontent over the 12-week abortion ban that the GOP-controlled state legislature passed last year

But Democrats have not won a presidential or U.S. Senate race in North Carolina since 2008. Despite Democratic gains in white-collar suburbs around Charlotte and Raleigh, Trumps campaign believes that a steady flow of conservative-leaning white retirees from elsewhere is tilting the state to the right; polls to this point consistently show Trump leading, often by comfortable margins.

Biden has a much greater area of vulnerable terrain to defend. In 2020, he carried three of his 25 states by less than a single percentage pointGeorgia, Arizona, and Wisconsinand won Pennsylvania by a little more than one point. He also won Michigan and Nevada by about 2.5 percentage points each; in all, Biden carried six states by less than three points, compared with just one for Trump. Even Minnesota and New Hampshire, both of which Biden won by about seven points, dont look entirely safe for him in 2024, though he remains favored in each.

Many operatives in both parties separate the six states Biden carried most narrowly into three distinct tiers. Biden has looked best in Wisconsin and Pennsylvania. Bidens position has been weakest in Arizona, Nevada, and Georgia. Michigan falls into its own tier in between.

This ranking and Trumps consistent lead in North Carolina reflect the upside-down racial dynamics of the 2024 race to this point. As Democrats always do, Biden still runs better among voters of color than among white voters. But the trend in support since 2020 has defied the usual pattern. Both state and national polls, as Ive written, regularly show Biden closely matching the share of the vote he won in 2020 among white voters. But these same polls routinely show Trump significantly improving on his 2020 performance among Black and Latino voters, especially men. Biden is also holding much more of his 2020 support among seniors than he is among young people.

These demographic patterns are shaping the geography of the 2024 race. They explain why Biden has lost more ground since 2020 in the racially diverse and generally younger Sun Belt states than he has in the older and more preponderantly white Rust Belt states. Slipping support among voters of color (primarily Black voters) threatens Biden in Michigan, Pennsylvania, and Wisconsin too, but the danger for him isnt as great as in the Sun Belt states, where minorities are a much larger share of the total electorate. Biden running better in the swing states that are less, rather than more, diverse is an irony that were not used to, says Bradley Beychok, a co-founder of the liberal advocacy group American Bridge 21st Century, which is running a massive campaign to reach mostly white swing voters in the Rust Belt battlegrounds.

Given these unexpected patterns, Democratic strategists Ive spoken with this year almost uniformly agree with Carville that the most promising route for Biden to reach 270 Electoral College votes goes through the traditional industrial battlegrounds of Michigan, Pennsylvania, and Wisconsin. If you look at all the battleground-state polling, and dont get too fixated on this poll or that, the polling consistently shows you that Biden runs better in the three industrial Midwest states than he does in the four swing Sun Belt states, Doug Sosnik, who served as the chief White House political strategist for Bill Clinton, told me.

Democratic hopes for a Biden reelection almost all start with him holding Pennsylvania and Wisconsin, where polls now generally show a dead heat. If Biden wins both and holds all the states that he won in 2020 by at least three pointsas well as Washington, D.C., and the Omaha congressional districtthat would bring the president to 255 Electoral College votes. At that point, even if Biden loses all of the Sun Belt battlegrounds, he could reach the 270-vote threshold just by taking Michigan, with its 15 votes, as well.

But Michigan has been a persistent weak spot for Biden. Although a CBS News/YouGov poll released Sunday showed Biden narrowly leading Trump in Michigan, most polls for months have shown the former president, who campaigned there today, reliably ahead. In all the internal polling Im seeing and doing in Michigan, Ive never had Joe Biden leading Donald Trump, Richard Czuba, an independent Michigan pollster who conducts surveys for business and civic groups, told me.

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Czuba doesnt consider Michigan out of reach for Biden. He believes that Robert F. Kennedy Jr., who has qualified for the ballot, will ultimately draw more votes from Trump. Democrats have also rebuilt a formidable political organization, he noted, while the state Republican Party is in disarray, which will help Biden in a close race. And defending abortion rights remains a powerful advantage for Democrats, Czuba said, with Governor Gretchen Whitmer an effective and popular messenger for that cause.

But Czuba said Biden is facing obstacles in Michigan that extend beyond his often-discussed problems with Arab American voters over the war in Gaza, discontent on college campuses around the same issue, and Trumps claim that the transition to electric vehicles will produce a bloodbath for the auto industry. Biden is also deeply unpopular among independents in the state, Czuba said concerns about his age are a principal concern. Thats the overriding issue were hearing, he told me. I dont think any of those independents voted for Joe Biden thinking he was going to run for reelection. On top of all that, Sundays CBS News/YouGov poll showed Trump winning about one in six Black voters in Michigan, roughly double his share in 2020.

If Biden cant win Michigan, his remaining options for reaching 270 Electoral College votes are all difficult at best. Many Democrats believe that if Biden loses Michigan, the most plausible alternative for him is to win both Arizona and Nevada, which have a combined 17 votes. Georgia or North Carolina, each with 16 votes, could also substitute for Michigan, but both now lean solidly toward Trump. After Michigan, or the combination of Arizona and Nevada, theres a fault line where the math works but the probabilities are pretty significantly lower, Sosnik said.

Public polls this spring arent much better for Biden in Arizona and Nevada than in Georgia and North Carolina. And just as Biden faces erosion with Black voters in the Southeast, hes underperforming among Latinos in the Southwest. Yet most Democrats are more optimistic about their chances in the Southwest than the Southeast.

In Nevada, thats partly because the Democrats turnout machinery, which includes the powerful Culinary Union Local 226, has established a formidable record of winning close races. Both states have also been big winners in the private-investment boom flowing from the three big bills Biden passed in his first two years in office: Nevada received $9 billion in clean-energy investments, and Arizona got a whopping $64 billion from semiconductor manufacturers. The sweep of Trumps plans for the mass deportation of undocumented immigrants could undo some of his gains with Latinos.

But mostly, Democratic hopes in both states center on abortion. Ballot initiatives inscribing abortion rights into the state constitution seem on track to qualify for the ballot in both, and polls show most voters in each state believe abortion should remain legal in all or most cases. In Arizona, the issue has been inflamed by the recent decision from the Republican-controlled state supreme court to reinstate a near-total ban on abortion dating back to 1864.

Beychok says a message of defending democracy and personal freedoms, including access to abortion and other reproductive care, remains Bidens best asset across the Sun Belt and Rust Belt swing states. Abortion, democracy, and freedom have been greater than whatever Republicans have decided to throw against the wall, he told me. They can go and scream about Bidens age, or the squad, or inflation and the cost of things. The problem is they have been singing that song for years and they have continued to lose elections.

If Biden has a path to a second term, those issues will likely need to clear the way againin the Rust Belt and Sun Belt alike.