In President Donald Trump's idealized framing, the United States was at its zenith in the 1890s. The Republican has said repeatedly, "We were at our richest from 1870 to 1913. That's when we were a tariff country." Trump points to decades after the Civil War, when the federal government ran frequent budget surpluses. Tariffs were then the government's main source of revenue and were high. But economists and historians say most of the era's growth was due to factors like the country's booming population, advances in technology and expansion of territory, which gave it new natural resources to exploit. They also say tariffs didn't play as large a role as Trump suggests.