What the overlay shows, and what it cannot. The background bands mark which party held the White House; the lines are the standard annual series: unemployment rate (BLS), real GDP growth (BEA), CPI inflation (BLS), and gross federal debt as a share of GDP (Treasury/OMB, right axis). The chart invites the obvious game, does the economy do better under one party, and the honest answer is that the chart cannot settle it. Presidents inherit the prior administration's economy with a lag; the Fed sets monetary policy independently (mostly); wars, pandemics, and oil shocks do not check party registration. The wartime boom of the 1940s, the 1970s stagflation that spanned three administrations of both parties, the 2008 collapse handed across an inauguration, and the 2020 pandemic all cut across the bands. What the chart does show cleanly is the debt ratchet: debt/GDP fell almost continuously from 1946 to 1974 under both parties, and has risen almost continuously since 1981 under both parties, with the steepest single climbs in 2008-2012 and 2020. The scarcinality reading: the postwar decline was growth outrunning the debt, not repayment; the post-1981 climb is the bill for suppressing every downturn's financial scarcity with borrowed demand. The bond market's patience with that ratchet is the standing question of the treatise's worked example. Figures for 2025-2026 are estimates from partial-year data.