Shortly after taking office, Gallatin worked with House Ways and Means Committee Chairman John Randolph to reduce federal spending and reduce or abolish all internal taxes, including the tax on whiskey. He presided over dramatic reductions in military spending, particularly for the United States Navy. Despite his opposition to debt, Gallatin strongly supported and arranged the financing for the Louisiana Purchase, in which the U.S. bought French Louisiana. Both Jefferson and Gallatin regarded control of the port of New Orleans, which was ceded in the purchase, as the key to the development of the Western United States. Jefferson had doubts about the constitutionality of the purchase, but Gallatin helped convince the president that a constitutional amendment authorizing the purchase was impractical and unnecessary. Gallatin also championed and helped plan the Lewis and Clark Expedition to explore lands west of the Mississippi River.