When American colonists rebelled against British rule in 1776, American merchant ships lost Royal Navy protection. With no American Navy for protection, American ships were attacked and their Christian crews enslaved by Muslim pirates operating under the control of the "Dey of Algiers"--an Islamist warlord ruling Algeria.
Because American commerce in the Mediterranean was being destroyed by the pirates, the Continental Congress agreed in 1784 to negotiate treaties with the four Barbary States. Congress appointed a special commission consisting of John Adams, Thomas Jefferson, and Benjamin Franklin, to oversee the negotiations.
Lacking the ability to protect its merchant ships in the Mediterranean, the new America government tried to appease the Muslim slavers by agreeing to pay tribute and ransoms in order to retrieve seized American ships and buy the freedom of enslaved sailors.
Adams argued in favor of paying tribute as the cheapest way to get American commerce in the Mediterranean moving again. Jefferson was opposed. He believed there would be no end to the demands for tribute and wanted matters settled "through the medium of war." He proposed a league of trading nations to force an end to Muslim piracy.
In 1786, Jefferson, then the American ambassador to France, and Adams, then the American ambassador to Britain, met in London with Sidi Haji Abdul Rahman Adja, the "Dey of Algiers" ambassador to Britain.
The Americans wanted to negotiate a peace treaty based on Congress' vote to appease.
During the meeting Jefferson and Adams asked the Dey's ambassador why Muslims held so much hostility towards America, a nation with which they had no previous contacts.
In a later meeting with the American Congress, the two future presidents reported that Ambassador Sidi Haji Abdul Rahman Adja had answered that Islam "was founded on the Laws of their Prophet, that it was written in their Quran, that all nations who should not have acknowledged their authority were sinners, that it was their right and duty to make war upon them wherever they could be found, and to make slaves of all they could take as Prisoners, and that every Musselman (Muslim) who should be slain in Battle was sure to go to Paradise." 
For the following 15 years, the American government paid the Muslims millions of dollars for the safe passage of American ships or the return of American hostages. The payments in ransom and tribute amounted to 20 percent of United States government annual revenues in 1800.
Not long after Jefferson's inauguration as president in 1801, he dispatched a group of frigates to defend American interests in the Mediterranean, and informed Congress.
Declaring that America was going to spend "millions for defense but not one cent for tribute," Jefferson pressed the issue by deploying American Marines and many of America's best warships to the Muslim Barbary Coast.
The USS Constitution, USS Constellation, USS Philadelphia, USS Chesapeake, USS Argus, USS Syren and USS Intrepid all saw action.
In 1805, American Marines marched across the desert from Egypt into Tripolitania, forcing the surrender of Tripoli and the freeing of all American slaves.
During the Jefferson administration, the Muslim Barbary States, crumbling as a result of intense American naval bombardment and on shore raids by Marines, finally officially agreed to abandon slavery and piracy.
Jefferson's victory over the Muslims lives on today in the Marine Hymn, with the line, "From the halls of Montezuma, to the shores of Tripoli, We fight our country's battles in the air, on land and sea."
It wasn't until 1815 that the problem was fully settled by the total defeat of all the Muslim slave trading pirates.
Jefferson had been right. The "medium of war" was the only way to put and end to the Muslim problem. He was a "visionary" wise enough to read and learn about the enemy from their own Muslim book of jihad. 
