Deflation
Deflation occurred periodically in the U.S. during the 19th century (the most important exception was during the Civil War). This deflation was at times caused by technological progress that created significant economic growth, but at other times it was triggered by financial crises — notably the Panic of 1837 which caused deflation through 1844, and the Panic of 1873 which triggered the Long Depression that lasted until 1879. These deflationary periods preceded the establishment of the U.S. Federal Reserve System and its active management of monetary matters. Episodes of deflation have been rare and brief since the Federal Reserve was created (a notable exception being the Great Depression) while U.S. economic progress has been unprecedented.
Economy of the United States
The United States has been the world's largest national economy in terms of GDP since at least the 1920s. For many years following the Great Depression of the 1930s, when danger of recession appeared most serious, the government strengthened the economy by spending heavily itself or cutting taxes so that consumers would spend more, and by fostering rapid growth in the money supply, which also encouraged more spending. Ideas about the best tools for stabilizing the economy changed substantially between the 1930s and the 1980s. From the New Deal era that began in 1933, to the Great Society initiatives of the 1960s, national policy makers relied principally on fiscal policy to influence the economy.
During the world wars of the twentieth century, the United States fared better than the rest of the combatants because none of the First World War and relatively little of the Second World War was fought on American territory (and none on the then 48 states). Yet, even in the United States, the wars meant sacrifice. During the peak of Second World War activity, nearly 40 percent of U.S. GDP was devoted to war production. Decisions about large swaths of the economy were largely made for military purposes and nearly all relevant inputs were allocated to the war effort. Many goods were rationed, prices and wages controlled and many durable consumer goods were no longer produced. Large segments of the workforce were inducted into the military, paid half wages, and roughly half of those were sent into harm's way.