Causes of the Great Depression
Second, there are the monetarists, who believe that the Great Depression started as an ordinary recession, but that significant policy mistakes by monetary authorities (especially the Federal Reserve) caused a shrinking of the money supply which greatly exacerbated the economic situation, causing a recession to descend into the Great Depression. Related to this explanation are those who point to debt deflation causing those who borrow to owe ever more in real terms.
Great Depression
The consensus view among economists and economic historians is that the passage of the Smoot-Hawley Tariff exacerbated the Great Depression, although there is disagreement as to how much. In the popular view, the Smoot-Hawley Tariff was a leading cause of the depression. However, many economists hold the opinion that the tariff act did not greatly worsen the depression.