This book examines the relationship between democracy and membership in the Missile Technology Control Regime (MTCR), a supply-side form of arms control. The book uses the focused comparison approach, investigating Brazil (a member ofthe MTCR) and the People's Republic of China (a non-member). Four independent variables are tested: democratic institutionalization; economic freedoms; norms, values, and beliefs; and elections. These are analyzed in each case and compared to the nation's decision to join the MTCR. The findings are that democracy, due to the effect of the independent variables, influenced and induced Brazil to join the MTCR; in contrast, the lack of democracy in China inhibits that country from joining. Brazil joined because of public desires for economic and material aid. These pressured the leadership to adhere, thus making the regime more effective. Therefore, the efforts to persuade China to join the MTCR might not succeed until it establishes democracy (including all four variables). This finding suggests that the U.S. National Security policy of "engagement and enlargement" is appropriate.