The creation of cartels increased globally after World War I. They became the leading form of market organization, particularly in Europe and Japan. In the 1930s, authoritarian regimes such as Nazi Germany, Italy under Mussolini, and Spain under Franco used cartels to organize their corporatist economies. Between the late 19th century and around 1945, the United States was ambivalent about cartels and trusts. There were periods of both opposition to market concentration and relative tolerance of cartels. During World War II, the United States strictly turned away from cartels. After 1945, American-promoted market liberalism led to a worldwide cartel ban, where cartels continue to be obstructed in an increasing number of countries and circumstances.