The generation of Americans that endured the Great Depression gained relief with the onset of the Second World War. War brought profound heartache for some, but for most it brought a resounding sense of national triumph and, more durably, a broad-based and rapidly increasing prosperity. Over the next thirty years, the American people (and, in fact, most of the people living in the old and the newly developing industrial nations) would experience the most sweeping material progress in the history of the world. Within twenty years of the war's conclusion, America's poor amounted to a small, scattered, and dwindling constituency with little evident political leverage. Even so, at precisely that time the national government launched an effort, unprecedented in the nation's history, to end or at least alleviate the effects of residual poverty in America.

Historically, poverty had been a mass phenomenon. In contrast, for the postwar United States – and also, by the mid-1950s, in Western Europe – it became a problem for a dwindling minority. In 1939, about half of American households dwelled in poverty. The war brought full employment and substantial increases in personal income, but in 1947 a third of Americans still lived in poverty.