Thomas Jefferson was a key architect of early American foreign policy. He had a clear vision of the place of the new republic in the world, which he articulated in a number of writings and state papers. The key elements to his strategic vision were geographic expansion and free trade. Throughout his long public career Jefferson sought to realize these ends, particularly during his time as US minister to France, secretary of state, vice president, and president. He believed that the United States should expand westward and that its citizens should be free to trade globally. He sought to maintain the right of the United States to trade freely during the wars arising from the French Revolution and its aftermath. This led to his greatest achievement, the Louisiana Purchase, but also to conflicts with the Barbary States and, ultimately, Great Britain. He believed that the United States should usher in a new world of republican diplomacy and that it would be in the vanguard of the global republican movement. In the literature on US foreign policy, historians have tended to identify two main schools of practice dividing practitioners into idealists and realists. Jefferson is often regarded as the founder of the idealist tradition. This somewhat misreads him. While he pursued clear idealistic ends—a world dominated by republics freely trading with each other—he did so using a variety of methods including diplomacy, war, and economic coercion.