White Flight From Trump? What a Decisive Biden Win Would Look Like

This sort of analysis offers only a rough idea of what could unfold. A demographic category like “white voters without a college degree,” however useful, encompasses an extremely diverse group of voters. They can move in meaningfully different directions, and there is no reason to assume that Mr. Biden’s strength would be felt equally in West Virginia and Vermont. Nonetheless, that’s exactly what this exercise does. A similar effort in previous years would not have anticipated the vagaries of real election outcomes, like Iowa moving 15 points to Mr. Trump while Wisconsin moved just eight points; or Indiana moving 22 points toward Barack Obama in 2008 while Ohio moved just seven points. This hypothetical offers only a rough guide to the kinds of districts that might be competitive.

But in this situation, Mr. Biden would win by 10 percentage points, 54 percent to 44 percent, and would win 375 votes in the Electoral College, including all of the states won by Mr. Obama in 2012, in addition to North Carolina, Georgia and Arizona. Mr. Biden’s weakness among nonwhite voters would leave Texas short of turning blue.

Notably, in such a hypothetical, Mr. Biden would also win by nine to 10 points in the three Northern battleground states that decided the last election: Pennsylvania, Michigan and Wisconsin. Four years ago, Mr. Trump fared better in these states than in the national popular vote, but this potentially decisive advantage in these relatively white states fades along with his lead among white voters.

This result would be close to current polling averages. Perhaps more surprising is how Mr. Biden would fare in a long list of traditionally Republican states and districts. He would fight to within single digits in Alaska, Utah, South Carolina, Indiana, Montana, Missouri and Kansas.

Again, it’s important to emphasize that these are rough estimates. But the prospect of somewhat competitive races in these states is borne out in recent polling: Mr. Trump leads by an average of seven points, 49 percent to 42 percent, in an average of 13 polls taken of these six states since mid-April, when Bernie Sanders left the Democratic contest.

It’s not terribly consequential whether Mr. Biden wins these states. But four of them have Republican-held Senate contests, and a strong showing by him would help Democratic chances further down the ballot. If Democrats actually could win one Senate race, most likely Montana, it would materially improve their ability to govern. It could even give them a serious chance to hold the chamber through Mr. Biden’s hypothetical first term, since the Republicans have relatively few opportunities to flip states in the 2022 midterm elections.

Republicans in the House may also face severe consequences. In this analysis, Mr. Biden would carry a staggering 260 congressional districts, including a half-dozen in Texas. He could even carry districts where Mr. Trump won by double digits in 2016, like Missouri’s Second, Indiana’s Fifth, Arizona’s Sixth, Florida’s 16th, or Ohio’s 12th and 14th. Mr. Trump would win another set of 25 districts by less than five points each. Many of these districts were only somewhat competitive in the 2018 midterms, while many others were not competitive at all. Already, various ratings outfits like the Cook Political Report have classified them as competitive.