Even though it was known that Jefferson was running for president and Burr for Vice President, whoever received the most votes would be elected as president. There was no provision that made it clear who was running for which office. This led directly to the passage of the 12th Amendment which corrected this problem. In 1803, Jefferson purchased the Louisiana territory from France for $15 million. This is considered the most important act of his administration. He sent Lewis and Clark on their famous expedition to explore the new territory. He also established the principle of executive privilege by refusing to testify during the Aaron Burr treason trial. Jefferson was the most gifted writer of his time and is displayed during the most important event of American History; the writing of the Declaration of Independence. http://www.whitehouse.gov/about/presidents/thomasjefferson
Presidential Years: 1801-1809