What were the accomplishments of President Jefferson’s administration that distinguished it from the previous two administrations?

Jefferson’s presidency is most notable because he, unlike his predecessors, chose to decentralize power from the federal government and return it to the respective states. Internationally, Jefferson tried desperately to keep the United States out of European conflict, specifically the Napoleonic Wars. However, Jefferson’s most notable act as the president of the United States would be the Louisiana Purchase, which doubled the size of the United States by purchasing the Louisiana Territory from France.
Unlike Washington, Jefferson chose to deliberately have a weak federal government, as he felt that a strong federal power would lead to tyranny. Jefferson used the example of Shay’s Rebellion as an example of excessive government power. Jefferson also, unlike John Adams, felt that a state had a right to cecede from the Union if a state’s sovereignty had been violated.

One great achievement of the Jefferson administration was his military mission against the Barbary Pirates in Tripoli. The last two administrations paid tribute to the pirates in order to peacefully trade in the Mediterranean. Jefferson, in a cost-cutting measure, sent the Marines to defeat the pirate states. This was the first United States action in the Middle East.
Jefferson also secured the port of New Orleans by buying the port as well as all of French Louisiana. While it is doubtful that Napoleon would have sold the territory if the slaves in Haiti had not revolted and declared their independence, Jefferson was able to take advantage of a key moment in world history in order to more than double the size of the United States. He did this without congressional approval, but it was too good of an opportunity to miss. Jefferson also sent explorers to the Pacific, thus mapping one of the first American overland routes across the continent.