In addition to the introduction of blended whiskeys and the Irish distillers' failure to account for its appeal to changing tastes, there were a number of additional issues which placed further pressure on the Irish distillers: the Irish War of Independence, the subsequent civil war, and trade war with Britain (which cut off whiskey exports to Britain and all Commonwealth countries, then Irish whiskey's biggest market); prohibition in the United States (1920-1933), which severely curtailed exports to Irish whiskey's second-biggest market; widespread counterfeiting of Irish whiskeys in America and Britain; protectionist policies introduced by the Irish Free State government, which significantly capped whiskey exports in the hope of taxing domestic consumption; and finally, over-expansion and mismanagement at several Irish distilleries. Together, these factors greatly hampered exports and forced many distilleries into economic difficulties and out of business, and by the early 20th century Scotland had surpassed Ireland to become the world's largest whiskey producer.