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.
Causes of the Great Depression
Protectionism, such as the American Smoot–Hawley Tariff Act, is often indicated as a cause of the Great Depression, with countries enacting protectionist policies yielding a beggar thy neighbor result. The Smoot–Hawley Tariff Act was especially harmful to agriculture because it caused farmers to default on their loans. This event may have worsened or even caused the ensuing bank runs in the Midwest and West that caused the collapse of the banking system. A petition signed by over 1,000 economists was presented to the U.S. government warning that the Smoot-Hawley Tariff Act would bring disastrous economic repercussions; however, this did not stop the act from being signed into law.