During the War of the Spanish Succession (1702-13), there were attempts to support colonial maritime war by legislation, and the American Act of 1708 can be seen as their culmination. Historians who study privateering or colonial history have referred to this act in several contexts, such as reform in prize administration, naval impressment in American colonies, and Spanish-American trade. However, the political and economic interests behind this act have not been fully investigated. By examining the process of the enactment of the American Act together with antecedent attempts to promote colonial maritime war in parliament, this article reveals the political and vested interests involved in the act, the relations between them, and the influence they had on the content of the act. This analysis will show the complex interaction between politics, trade, and colonial maritime war in the early-18th-century American colonies.