During World War I, most countries, including the United States, effectively abandoned the gold standard to finance their wartime expenditures. This led to a massive drop in demand for gold and thus a large drop in its value. After the war ended, the countries sought to reconstitute the system. Hawtrey in 1919 and Gustav Cassel (independently in 1920–21) warned that restoring the gold standard without a simultaneous policy of restricting the international monetary demand for gold would push up gold prices and result in a deflationary crisis.