The packing premium collapsed

Share of each party's two-party votes cast in precincts it won by 60+ points (an 80–20 landslide), by cycle. The shaded gap is the Democratic packing premium.

Mode-safe two-party precinct returns (MEDSL). The Republican share is roughly flat across the three cycles; the Democratic share falls by nine points, closing the gap from 11.6 to 3.0. "Packing" here is descriptive geography, not a redistricting claim — but it is the same quantity that makes Democratic votes electorally inefficient.

Where the votes piled up, three cycles

Share of the two-party vote cast in precincts of each margin, by year. Same election geography, viewed as a distribution.

Two-party margin = (Dem − Rep)/(Dem + Rep), vote-weighted; each curve integrates to 100%. The right (Democratic) tail thins markedly between 2016 and 2024 while the left (Republican) tail is comparatively stable — and the competitive center fills in. A naive read of the Big Sort would predict the opposite.

Change in how divided each county is inside, 2016→2024

Vote-weighted standard deviation of a county's precinct margins in 2024 minus 2016, in points. Teal = neighborhoods converged; orange = pulled further apart. Counties need 10+ reported precincts in both years; others are beige.

2,341 counties qualify. The convergence is broad but concentrated in and around metropolitan areas; rural counties, already homogeneous, had little room to converge. Individual county values are noisier than the national pattern because precinct boundaries are redrawn between cycles — read the color field, not single counties.

The unpacking was concentrated in the metro core

Change 2016→2024 in the share of a county's Democratic votes cast in its 80–20 precincts, vote-weighted mean by USDA urbanization class.

USDA Rural–Urban Continuum Codes (2024 county classification): "Large metro core" = code 1; "Other metro" = 2–3; "Small metro / micro" = 4–6; "Rural" = 7–9. Bars are negative everywhere — packing fell across the board — but the metro core fell roughly ten times as far as the countryside.