People on both the left and the right claim the president possesses significant, unilateral power over military action, and they support this myth by perpetuating a big lie – that Thomas Jefferson did the same in response to the Barbary Pirates. 

But like so many other myths about expansive federal power, historical truth doesn’t back up this commonly held narrative. In fact, Jefferson deferred to Congress throughout the Barbary conflict.


The Constitution vests the power to “declare war” in Congress. The founders understood this to mean changing the state of things from peace to war. This could occur through words or actions.

As Thomas Jefferson wrote, “Congress alone is constitutionally invested with the power of changing our condition from peace to war.”

Some argue that if another country declares war – whether in word or by deed – this action by the other country changes the state of things from peace to war, empowering the president to act with offensive measures without any congressional input. But Jefferson disagreed, leaving the decision of how to respond to such outside declarations of war to the representatives of the people and the states. We can see this by the way he responded to the Barbary pirates


By the time Jefferson took office, aggression against U.S. shipping off the coast of Africa had been going on for years, with pirates of the Barbary States preying on American ships. European countries had experienced much of the same, and negotiated peace with the states by paying tribute – sums of money that were effectively ransoms to protect their shipping. 

Before his presidency, Jefferson had been involved in negotiating with the aggressors, and he did not support paying tribute. Jefferson expressed his sentiments in a letter to James Monroe on Nov. 11, 1784.

“We have taken some pains to find out the sums which the nations of Europe give to the Barbary states to purchase their peace. They will not tell this; yet from some glimmerings it appears to be very considerable; and I do expect that they would tax us at one, two, or perhaps three hundred thousand dollars a year. Surely our people will not give this. Would it not be better to offer them an equal treaty? If they refuse, why not go to war with them?” [emphasis added]

A month later, having learned that a small American brig had been seized by a Moroccan corsair in the Atlantic, Jefferson again emphasized the hard line in a letter to Horatio Gates:

“Tribute or war is the usual alternative of these pirates. If we yield the former, it will require sums which our people will feel. Why not begin a navy then and decide on war?”

Jefferson’s view notwithstanding, in the years to follow, President John Adams negotiated treaties with several Barbary states including Algiers and Tripoli, with the latter getting a payment of $18,000/year.

But, as Jefferson warned in 1784, such a deal would never be enough, and Pasha Yusuf Karamanli of Tripoli felt like he got the short end of the stick. Within a year of the deal with the Adams administration – and a full five months before Jefferson took office – the Pasha demanded significantly more money and began taking an increasingly aggressive stance against the U.S. 


The U.S. consul in Tripoli James Cathcart wrote to the Secretary of State on Oct. 7, 1800, that the Pasha said “If you don’t give me a present I will forge a pretext to capture your defenseless merchantmen.” 

Just a week later, Tripoli proved their intentions when they captured another American ship. But, possibly it was just a warning, as the crew was released immediately.

By Feb. 21, 1801, Cathcart was warning that war was imminent. In a Circular to the Consuls and Agents of the United States, he wrote “I am convinced that the Bashaw of Tripoli will commence Hostilitys against the U. States of America in less than Sixty Days.”

In the meantime, just before Jefferson’s inauguration in 1801, Congress passed “An Act Providing for a Naval Peace Establishment,” legislation providing for six frigates that “shall be officered and manned as the President of the United States may direct.”


In a meeting on May 15, 1801, Jefferson and his cabinet discussed what options were available to them under the Constitution. In attendance were Attorney General Levi Lincoln, Secretary of the Treasury Albert Gallatin, Secretary of State James Madison, and Acting Secretary of the Navy Samuel Smith. The entire cabinet agreed that ships should be sent out – and if war was declared, to use defensive measures.

Lincoln’s position was the most reserved, “Our men of war may repel an attack on individual vessels, but after the repulse, may not proceed to destroy the enemy’s vessels generally.”

Jefferson’s notes also included this:

“Whether the captains may be authorized, if war exists, to search for & destroy the enemy’s vessels wherever they can find them?—all except mr L—agree they should; M. G. & S. think they may pursue into the harbours, but M. that they may not enter but in pursuit.” [emphasis in original]

In short – only in a state of war, did anyone in the cabinet believe the Jefferson administration was authorized to respond with force. And even there, Lincoln held that an attack could be repelled, but they couldn’t search for the enemy, and Madison held they weren’t even authorized to enter into enemy harbors except in an active pursuit.

By May 20, Smith sent orders from the President to Commodore Richard Dale to sail to Tripoli along with an offer of peace. 

Jefferson’s letter to the Pasha opened with “Great and Respected Friend.”

“The assurances of friendship which our Consul has given you, & of our sincere desire to cultivate peace & commerce with your subjects, are faithful expressions of our dispositions, and you will continue to find proofs of them in all those acts of respect & friendly intercourse which are due6 between nations standing as we do in the relations of peace & amity with each other”

He also explained that he was sending this squadron to observe the situation and “superintend the safety of our commerce.” Jefferson also made clear that peace could be the order of the day and the squadron was given strict orders on these lines:

“We have yet given them in strict command to conduct themselves towards all friendly powers with the most perfect respect & good order it being the first object of our sollicitude to cherish peace & friendship with all nations with whom it can be held on terms of equality & reciprocity.”

At the same time, Commodore Dale was also given specific orders on how to proceed if he found that war had already been declared against the United States:

“Should the bey of tripoli have declared war (as he has threatened) against the united states – you will then proceed direct to that Port, where you will lay your ships in such a position as effectually to prevent any of their vessels from going in or out. The essex and enterprise by cruising well on towards tunis will have it in their power to intercept any vessels which they may have captuers”


That’s exactly what happened in the meantime, on May 14, 1801.

The following day, Cathcart sent out a circular, to inform others that the Pasha of Tripoli declared war on the United States:

“I am sorry to inform you that our Flagstaff was chop’d down upon Thursday the 14th instant and War was declared in form by the Bashaw of Tripoli against the United States of America” [emphasis added]

When the squadron arrived in the area on July 1, Commodore Dale learned that the Pasha had already declared war, and proceeded to take the defensive actions per the instructions from Pres. Jefferson via Sec. Smith.

Dale’s blockade of the port of Tripoli ran until early September, and during that time, Andrew Sterret, captain of the USS Enterprise, won the first American victory of the war, in its only battle of 1801. Because Congress had not yet responded to Tripoli’s declaration of war with one of their own, Sterret could not take the 14-gun corsair Tripoli as a prize. Instead, after winning the battle, he ordered the ship disarmed, throwing its guns overboard, and then released the crew and the ship. 


Despite this battle, the previous attacks, and the formal declaration of war by Tripoli against the United States, Jefferson was firm in his position that he was still “unauthorized by the Constitution, without the sanction of Congress, to go beyond the line of defense.”

In his First Annual Message to Congress, he continued, requesting authorization from Congress to go further.

“The Legislature will doubtless consider whether, by authorizing measures of offense also, they will place our force on an equal footing with that of its adversaries. I communicate all material information on this subject, that in the exercise of this important function confided by the Constitution to the Legislature exclusively their judgment may form itself on a knowledge and consideration of every circumstances of weight.”

Less than 2 months later, Congress did just that.

On Feb. 6, 1802, Congress passed an “Act for the Protection of American Commerce and Seamen,” authorizing some limited offensive measures against Tripoli:

“It shall be lawful for the President of the United States to instruct the commanders of the respective public vessels aforesaid, to subdue, seize and make prize of all vessels, goods, and effects, belonging to the Bey of Tripoli, or to his subjects, and to bring or send the same into port, to be proceeded against, and distributed according to the law; and also to cause to be done all such other acts of precaution or hostility as the state of war will justify, and may, in his opinion, require.”

Only after requesting, and eventually receiving, this authorization for offensive war measures from Congress, did President Jefferson order the Navy to take such actions. On Feb 18, 1802, Jefferson sent a “Circular to Naval Commanders” with instructions on what they were authorized to do.

“THEREFORE, And in pursuance of the said statute, you are hereby authorized and directed to subdue, seize, and make prize, of all vessels, goods, and effects, belonging to the Bey of Tripoli, or to his subjects, and to bring or send the same into port, to be proceeded against and distributed according to law. “

In his Second Annual Message to Congress, Jefferson discussed the situation in Tripoli once again, clearly noting that “warfare” was ongoing. Yet, he still took a very restrained and limited approach.

“There was reason not long since to apprehend that the warfare in which we were engaged with Tripoli might be taken up by some other of the Barbary Powers. A reenforcement, therefore, was immediately ordered to the vessels already there. Subsequent information, however, has removed these apprehensions for the present. To secure our commerce in that sea with the smallest force competent, we have supposed it best to watch strictly the harbor of Tripoli. Still, however, the shallowness of their coast and the want of smaller vessels on our part has permitted some cruisers to escape unobserved, and to one of these an American vessel unfortunately fell prey. The captain, one American sea man, and two others of color remain prisoners with them unless exchanged under an agreement formerly made with the Bashaw, to whom, on the faith of that, some of his captive subjects had been restored.”

In the following years, Congress passed multiple statutes to authorize additional actions, including a March 26, 1804 “Act further to protect the commerce and seamen of the United States against the Barbary powers,” which gave explicit support for “warlike operations against the regency of Tripoli, or any other of the Barbary powers.” 


Note that these narrow congressional authorizations were explicit and described specific actions the president could take. They guided his decision-making and gave him very little discretion. They didn’t authorize Jefferson to take whatever steps he deemed necessary or to decide when and if he wanted to go to war. Congress engaged in the decision-making and Jefferson executed its will.

The historical events reveal Thomas Jefferson’s true view on war powers under the Constitution.

  1. Congress “exclusively” decides whether or not the country will engage in war. Not the president.
  2. The President can use the military to respond to attacks, but can not go “beyond the line of defense”
  3. Even if a war is declared by a nation against the United States, the president cannot go “beyond the line of defense” – and must get authorization from Congress to engage in “measures of offense.”
Michael Boldin

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