The election of 1800 was fiercely contested and facilitated the rise of the two-party system and bitter partisanship.
Upon entering office, Jefferson focused on reducing the national debt he had inherited from his predecessors. His administration lowered excise taxes while slashing government spending. Additionally, the Jefferson administration reduced the size of the Navy, ultimately bringing the national debt down from $83 to $57 million. Foreign developments, however, including the intensification of piracy along the Barbary Coast, would necessitate the rebuilding of the Navy and its establishment as a permanent part of the US government.
Jefferson dealt with two major challenges to US authority: piracy along the Barbary Coast of North Africa, and British impressment, which resulted in Jefferson instating a mass embargo of European goods, the Embargo Act of 1807.
Jefferson authorized the Louisiana Purchase, which effectively doubled the territory of the United States.