Long Depression
Nobel laureate economist Milton Friedman, author of "A Monetary History of the United States", on the other hand, blamed this prolonged economic crisis on the imposition of a new gold standard, part of which he referred to by its traditional name, The Crime of 1873. This forced shift into a currency whose supply was limited by nature, unable to expand with demand, caused a series of economic and monetary contractions that plagued the entire period of the Long Depression. Murray Rothbard, in his book "History of Money and Banking of the United States", argues that the long depression was only a misunderstood recession since real wages and production were actually increasing throughout the period. Like Friedman, he attributes falling prices to the resumption of a deflationary gold standard in the U.S. after the Civil War.
Tariff
Milton Friedman held the opinion that the Smoot–Hawley tariff of 1930 did not cause the Great Depression, instead he blamed the lack of sufficient action on the part of the Federal Reserve. Douglas A. Irwin wrote: "most economists, both liberal and conservative, doubt that Smoot–Hawley played much of a role in the subsequent contraction".
Peter Temin, an economist at the Massachusetts Institute of Technology, explained that a tariff is an expansionary policy, like a devaluation as it diverts demand from foreign to home producers. He noted that exports were 7 percent of GNP in 1929, they fell by 1.5 percent of 1929 GNP in the next two years and the fall was offset by the increase in domestic demand from tariff. He concluded that contrary the popular argument, contractionary effect of the tariff was small.
William Bernstein wrote: "Between 1929 and 1932, real GDP fell 17 percent worldwide, and by 26 percent in the United States, but most economic historians now believe that only a miniscule part of that huge loss of both world GDP and the United States’ GDP can be ascribed to the tariff wars. .. At the time of Smoot-Hawley's passage, trade volume accounted for only about 9 percent of world economic output. Had all international trade been eliminated, and had no domestic use for the previously exported goods been found, world GDP would have fallen by the same amount — 9 percent. Between 1930 and 1933, worldwide trade volume fell off by one-third to one-half. Depending on how the falloff is measured, this computes to 3 to 5 percent of world GDP, and these losses were partially made up by more expensive domestic goods. Thus, the damage done could not possibly have exceeded 1 or 2 percent of world GDP — nowhere near the 17 percent falloff seen during the Great Depression... The inescapable conclusion: contrary to public perception, Smoot-Hawley did not cause, or even significantly deepen, the Great Depression.