R +20D +20
Counties vote by how densely people live. Sort ~3,100 counties into log₂(density) buckets and the Democratic share rises along one durable curve, crossing 50% near 800 people per square mile. Slide the crossover to see how far down the density ladder a candidate has to win to reach 270.
In this model, the difference between Harris's 226 and a 270 win is about +1 point of vote share in counties at the 2024 line. The candidate presets sit at −0.4 (800), −2.6 (1,000) and −4.5 points (1,200). Published estimates of what ideology is worth in a general election:
More in Common's Hidden Tribes survey finds the same concentration by political temperament. Its most engaged segment, Progressive Activists, is 8% of adults but, on our calculation from the report's turnout data, about a quarter of 2018 Democratic voters. That matches the survey above, where 25–31% of Democratic primary voters call themselves very liberal. Progressive Activists outnumber Devoted Conservatives about 3 to 1 in cities, 1.2 to 1 in suburbs, and 0.6 to 1 in rural areas (self-described place type). Weighted by turnout, the two wings are a third of adults but about 44% of voters (Hidden Tribes, 2018; the segment shares have not been re-estimated since).
Who votes in primaries is contested too. Moderates are 47% of voting-age adults but 11% of decisive primary voters across both parties (Unite America). Yet 34% of Democratic primary voters call themselves moderate and 60% lack a college degree (Third Way). In New York, Zohran Mamdani won the 2025 primary on turnout in affluent, dense neighborhoods and then needed Cuomo's primary voters to win the general with 50.8% (Caley). Michigan's 2026 Senate race, where Abdul El-Sayed won the primary, is the next test.
| Election | Crossover | Polarization | Replayed on 2028 map |
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| Strategy, from the current settings | Electoral votes |
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"Dense" is phased in around the 2024 line (767/sq mi on the county measure), so it includes inner suburbs as well as cities.
Each past election keeps its measured crossover. Polarization is the stretch of the 2024 curve that best fits that year's buckets. Both are then run on today's counties with 2024 county history. Democrats won in 2008 and 2020 by moving the crossover down, not by running up city margins.
Dots: mean Democratic two-party share of counties in each log₂ density bucket for the selected year. Faint lines: every election 2000–2024. Solid line: the curve the model is using now.
States ordered from most to least Democratic under the current settings. The highlighted row is where the Democrat's running total passes 270.
| Unit | EV | D total | Margin |
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