Capital swings one way, the wage subsidy the other

ZCTAs sorted into ten equal groups by their capital-gains-return share (blue) and, separately, by their EITC-return share (red). Each point is the turnout-weighted mean 2016→2020 presidential swing (positive = toward Democrats).

Takeaway: climb the capital-gains ladder and a ZIP code’s vote moved toward Biden; climb the EITC ladder and it moved toward Trump. The lines cross near the middle of the income-composition spectrum.

ZCTA-level 2020 and 2016 presidential estimates (precinct returns allocated to ZCTAs) joined to IRS Statistics of Income ZIP-code aggregates. Deciles formed within ZCTAs reporting both shares (n = 27,170); each decile holds 2,717 ZCTAs. Source: see notes.

The level is U-shaped — both extremes already lean blue

The same deciles, now plotted against the 2020 two-party presidential margin (positive = Democratic). For both variables the relationship is U-shaped: the lowest and highest deciles lean Democratic while the middle leans Republican.

Takeaway: this is a story about which places moved, not a simple level reversal. The very poorest and the very richest ZIP codes both voted Democratic in 2020; the swing, not the level, is what the income mix predicts.

Same ZCTAs and weights as the hero; the y-axis here is the 2020 level margin rather than the 2016→2020 swing. The U-shape is why the level cannot be read as a poor-to-rich ladder. Source: see notes.