Yglesias makes a provocative argument that the United States – far from being overpopulated – is underpopulated compared to other leading nations and should aim to expand its population to around one billion by the end of the century to maintain economic vitality, geopolitical power, and innovation leadership. He advocates for a sweeping policy agenda including liberalised immigration, robust support for family formation (childcare, parental leave, subsidies), and a national housing and infrastructure overhaul that dismantles restrictive zoning, boosts urban density, and revitalises struggling Rust Belt cities. Yglesias leans on the economic benefits of scale and agglomeration – more people enable broader labour markets, specialised services, and more efficient provision of public goods – while promising that even a billion strong America would still be no denser than France.