In the Depression, according to Kindleberger, the US should have provided an open market to foreign goods. Instead, the Smoot-Hawley Tariff Act closed off American markets and provoked other countries into a spiral of retaliatory trade measures.
照金德博格所说，在大萧条期间美国本应对国外商品开放市场，但斯穆特-哈维关税法案却反其道而行之，导致其他国家也开始推行一连串报复性贸易政策，且政策的严厉程度随着事态的发展而不断升级。