Zarqawi died a pirate on the Barbary Shore of our time, hoisted and displayed digitally like a blackguard on the gallows. His death continues a 500-year-old tradition of extortion and retribution between the great Western powers and the ever-enterprising ummah.

What does it mean that Zarqawi was a pirate captain in the service of pirate kingdoms? It means that today what we call the war on terror is recognizable as an especially dangerous version of the slave trade and tribute system worked up by our pragmatic forbears.

Starting from 1492, the Barbary states of North Africa dispatched their raiders to abduct and enslave white Christians. Captives in the millions suffered demonic cruelty in the dungeons and slave galleys of Sallee, Algiers and Tripoli. A useful Moorish logic said the mayhem was a form of jihad against the infidels; it was also a source of healthy labor and the occasional pricey ransom paid by royalty. The courts and merchants of the Mediterranean and Atlantic didn’t much protest; and by the end of the 18th century there was an efficient system of tribute paid to the emirs that kept the mayhem at an acceptable rate. The Barbary Shore had become a market.

Young America turned its face to the Barbary Shore with unhesitant obeisance. Washington, John Adams, Jefferson, and Madison paid tribute because it was cheaper than paying for an American fleet. The 1803 hostage rescue operation we remember as the Marines campaigning “to the shores of Tripoli” did not interrupt the transfer of gold and arms. What finally threatened Madison enough to act boldly was the maritime fracas we recall as the War of 1812, when the bloody-minded English told the Dey of Algiers he was free to sink American shipping. Madison fumed, and after the peace was signed with Britain, the president deployed Stephen Decatur’s squadron to persuade Algiers by force that the bribes were discontinued for now. (These stories are told vibrantly by Frederick C. Leiner in “The End of the Barbary Terror.”)

What I take from all this infamy and expedience is not that the Barbary piracy failed, but that it succeeded so effectively that it has been adopted by ambitious Islamic states ever since. The 19th century was one expensive tangle of either propping up or conniving over the Barbary states and the infamous sick man of Europe, the Ottoman Empire. After the First World War, the Versailles Peace Conference sliced up the ummah like a birthday cake. The market of the extortionists exploded to a global scale with the discovery of oil and the installation of cooperative emirates from Cairo to Riyadh to Islamabad. Yet for every pay-as-you-go minded chieftain, such as the Hashemites of Arabia or Ataturk of Turkey, there were the rascals who wanted more than their share. What were Nasser of Cairo and Arafat of Palestine or Hussein of Baghdad if not Barbary extortionists demanding cash and armaments to keep them from wrecking their neighborhoods and the oil markets of Europe and North America?

America and its coalition are paid up to date with blood and treasure in the new version of the tribute system called the war on terror. Zarqawi swings, and we cheer our Decaturs and their laser-guided cannon balls. When the deranged Bin Laden or the schoolmarmish Zawahiri are taken and hanged, it will also be celebrated as a triumph of geopolitical order that sometimes paying up a little for war is better than paying off a lot for homicides and blackmailers.

Even Tehran, now fancying itself as Algiers reawakened as it negotiates a price for hemkissing, will fall into line eventually. Why? Because if Tehran goes too far in its shakedown schemes and defies the great powers, it may well suffer the same kind of fate as the Dey of Algiers in 1816, a year after Madison and Decatur negotiated a cease and desist. Flush with the victory over Bonaparte, England dispatched a combined Anglo-Dutch squadron from Gibraltar under the resolute Admiral Lord Exmouth to clear out the Barbary shore of abductors. Anchored at gun range at Algiers, Exmouth sent an ultimatum that gave the dey a few hours to humble himself, which he recklessly refused. England proceeded with a cannonade that flattened the city’s defenses – a caution to Tehran that the real short-fused gang might be those infidels of Europe who set price limits on piracy.

Mr. Batchelor is host of “The John Batchelor Show” on the ABC radio network. The show airs in New York on 770 AM from 10 p.m. to 1 a.m.