Ideas about free trade and open commerce drove early American foreign policy before the War of 1812. Concern with expansion was not entirely absent from American diplomacy, but until the 1820s, 30s and 40s, it played a less significant role in foreign policy decisions than trade. Before the Revolutionary War both the British and American believed that their empire was based on commerce and not conquest. They engaged in wars for empire determined to secure the colonies from outside threats and to defend commerce. The American Revolution began in controversies over the regulation of commerce and taxation (usually connected to trade as well). The Revolutionaries sought to establish a new diplomatic regime based on free trade. They persisted in this concern in the creation of the Confederation government and with the establishment of the American republic under the Constitution of 1787. All of the major treaties between the United States and other nations before 1812 concerned commerce, even when they included territorial acquisition. The Louisiana Purchase began as an effort to secure commerce on the Mississippi by gaining the port of New Orleans. Conquest first emerged as the salient policy in dealing with Native Americans, and was then extended to Florida, Texas, and northern Mexico thereafter. However, even when manifest destiny had become the focus of American foreign policy, commerce and free trade remained important.