When the war began, the U.S. economy was in recession. But a 44-month economic boom ensued from 1914 to 1918, first as Europeans began purchasing U.S. goods for the war and later as the United States itself joined the battle. "The long period of U.S. neutrality made the ultimate conversion of the economy to a wartime basis easier than it otherwise would have been," writes Rockoff. "Real plant and equipment were added, and because they were added in response to demands from other countries already at war, they were added precisely in those sectors where they would be needed once the U.S. entered the war."
