On Jefferson's inauguration as president in 1801, Yusuf Karamanli, the Pasha (or Bashaw) of Tripoli, demanded $225,000 from the new administration. (In 1800, Federal revenues totaled a little over $10 million.) Putting his long-held beliefs into practice, Jefferson refused the demand. Consequently, in May 1801, the Pasha declared war on the U.S., not through any formal written documents but in the customary Barbary manner of cutting down the flagstaff in front of the U.S. Consulate. Algiers and Tunis did not follow their ally in Tripoli.
In response, Jefferson sent a group of frigates to defend American interests in the Mediterranean, and informed Congress. Although Congress never voted on a formal declaration of war, they did authorize the President to instruct the commanders of armed American vessels to seize all vessels and goods of the Pasha of Tripoli "and also to cause to be done all such other acts of precaution or hostility as the state of war will justify."
Enterprise capturing Tripoli
The schooner USS Enterprise defeated the 14-gun Tripolitan corsair Tripoli after a fierce but one-sided battle on August 1, 1801.
In 1802, in response to Jefferson's request for authority to deal with the pirates, Congress passed "An act for the Protection of Commerce and seamen of the United States against the Tripolitan cruisers", authorizing the President to "... employ such of the armed vessels of the United States as may be judged requisite ... for protecting effectually the commerce and seamen thereof on the Atlantic ocean, the Mediterranean and adjoining seas."
The U.S Navy went unchallenged on the sea, but still the question remained undecided. Jefferson pressed the issue the following year, with an increase in military force and deployment of many of the Navy's best ships to the region throughout 1802. The USS Argus, Chesapeake, Constellation, Constitution, Enterprise, Intrepid, Philadelphia and Syren all saw service during the war under the overall command of Commodore Edward Preble. Throughout 1803, Preble set up and maintained a blockade of the Barbary ports and executed a campaign of raids and attacks against the cities' fleets.