And even if we weren't, the Barbary Pirates were acting under orders from the rulers of local nations (who declared war on us, btw. ) Indeed, it only happened in the first place because when Adams and Jefferson met with the Algierian Ambassador to negotiate ransoms he informed them they could purchase peace through tribute (a tribute we really couldn't afford. ) Incidentally, when Jefferson asked why they attacked a nation that had done them no hurt, he was informed that, "It was written in their Koran, that all nations which had not acknowledged the Prophet were sinners, whom it was the right and duty of the faithful to plunder and enslave; and that every muslim who was slain in this warfare was sure to go to paradise. "

A better parallel would be the modern Somali pirates, but while a number of militaries are combating them in conjunction with ours, no one has suggested invading Somalia to hold them responsible. Why? Because there's no government worthy of the name to sue for peace; IF we invaded Somalia and IF we got their government to sign a peace treaty (as we did the leaders of the Barbary States after both of those wars) that government would still be largely powerless to stop the piracy of its citizens (which the Barbary States could and did do easily. ) Somalia, as a nation, is not responsible for what murderous, amoral and INDIVIDUAL Somalias do, even in international waters. That Al Qaeda operates without borders, in secret, with ample laundered monies and clandestine training so they can murder anywhere on Earth makes them no more a national army than it does the Italian Mafia. Which, I might add, is a lot bigger, wealthier and has murdered more people than Al Qaeda. The only difference is motive, which is really irrelevant; if the Mafia rechristened violent crime as holy war it would remain illegitimate and illegal, and would make them neither nation nor army. So when do we haul Burlesconi and the Pope out of their spiderholes...?