WILLIAM GALSTON: President Biden’s Fraying Coalition.

Broadly speaking, the coalition that gave Mr. Trump 47% of the vote in 2020 remains intact, while Mr. Biden’s winning coalition has frayed significantly. According to the New York Times/Siena poll, 97% of those who voted for Mr. Trump four years ago intend to do so again in 2024, compared with 83% for Mr. Biden. Ten percent of Mr. Biden’s former supporters say that they will switch to Mr. Trump. This helps explain the top-line numbers: Mr. Biden outpolled Mr. Trump in 2020 by nearly 4.5 points but now trails him by 2.1, a 6.6-point swing.

Key blocs in the Democratic coalition have eroded. In 2020 Mr. Biden won 18- to 29-year-old voters by 24 points; now his lead is half that. He won in the suburbs by 11 points but leads by only 2 now. His lead among black voters has fallen from 84 points to just 43, and it would be a historic shift if Mr. Trump comes anywhere near the 23% support the poll found. Mr. Biden prevailed among Hispanic voters by 21 points in 2020 but now trails by 6 in this expanding group.

This result for Hispanics may seem hard to believe, but it’s consistent with other findings. Only 16% of Hispanics say that economic conditions are excellent or good compared with 84% who rate them as fair or poor. Only 31% approve of Mr. Biden’s performance as president; 67% disapprove. A tougher approach to immigration is no deal-breaker: 45% of Hispanics favor making it harder to seek asylum at the southern border, nearly as many as the 47% who oppose it. Ideologically, Hispanics are to the right of the Democratic Party: Only 20% describe themselves as liberal, vs. 44% as moderate, and 30% as conservative.

The fraying of the Biden coalition is evident in the swing states as well.

What doesn’t show up in the polls is dirty tricks, so don’t get cocky.