There is no justification anywhere in the Constitution for waging war. It just says the Congress must declare war. That has rarely happened even when the USA was in its infancy. There was no declaration of war for the actions against the Barbary Pirate, or the French in the “Quasi War” we fought with both. Both wars happened while founding fathers were presidents.
“Thomas Jefferson did not seek or obtain a formal declaration of war from Congress against the Barbary Pirates (specifically during the First Barbary War against Tripoli, 1801–1805) primarily due to his strict interpretation of the U.S. Constitution and his commitment to limiting executive power in matters of war.
The U.S. Constitution (Article I, Section 8) grants Congress the sole power “to declare War.” Jefferson, a strict constructionist who believed in a limited federal government, viewed a formal declaration of war as Congress’s exclusive prerogative. He was unwilling to initiate offensive war on his own authority without congressional approval.
Key events unfolded as follows:
• In May 1801, shortly after Jefferson’s inauguration, the Pasha of Tripoli (Yusuf Karamanli) demanded higher tribute payments. When Jefferson refused (consistent with his long-held opposition to paying tribute, which he saw as ineffective and humiliating), the Pasha symbolically declared war by chopping down the flagpole at the U.S. consulate in Tripoli.
• Jefferson had already sent a naval squadron to the Mediterranean in early 1801 (with pre-existing congressional authorization for naval forces to protect commerce), but he limited initial actions to defensive measures.
• In his December 1801 message to Congress, Jefferson reported the events and explicitly stated he was “unauthorized by the Constitution, without the sanction of Congress, to go beyond the line of defense.” He released a captured Tripolitan vessel after an engagement because he lacked offensive authorization.
• Rather than asking Congress for a formal declaration of war (which might have been politically difficult or unnecessary for a limited naval conflict), Jefferson requested authority for offensive actions to protect U.S. commerce and seamen.
• In February 1802, Congress passed “An Act for the Protection of Commerce and Seamen of the United States against the Tripolitan Cruisers.” This authorized the president to use armed vessels to seize Tripolitan ships, goods, and to take other hostile acts as justified by the state of war—effectively a limited authorization for war without a full declaration.
Congress never issued a formal declaration of war against Tripoli (or the other Barbary states involved). The conflict remained a limited naval war, often described as a “quasi-war” or police action against piracy. This approach aligned with Jefferson’s principles: he deferred to Congress for expanding hostilities, avoided overreach, and achieved his goal of ending tribute payments through force without a politically charged full declaration.
In short, Jefferson didn’t pursue a declaration because Tripoli had already declared war (prompting a defensive response), he respected congressional war powers, and the 1802 authorization sufficed for the naval campaign he needed. This set an early precedent for presidents using force abroad with congressional backing short of formal war declarations.”