During the 1920s and early 1930s, Japan progressed toward a democratic system of government. However, parliamentary government was not rooted deeply enough to withstand the economic and political pressures of the 1930s, during which expansionism and militarization became increasingly influential in government and society. The U.S. State Department Central Classified Files are the definitive source of American diplomatic reporting on political, military, social, and economic developments throughout the world in the twentieth century.