What happened last time is always a good and often the best guide to what will happen this time. People hate this.
When U.S. embassies in Africa were bombed, the United States responded by firing cruise missiles over Pakistan into Afghanistan, to no discernible effect. When, a year or so later, the U.S.S. Cole was attacked, the United States elected to not do much of anything--and it is now reaping what it sowed: the seed of complacency has blossomed into a harvest of death.
Perhaps if the military response after the embassy bombings had been more effective, or if there had been a military response after the U.S.S. Cole attack, the very individuals who hijacked and flew the aircraft on Tuesday would have been solved by it.
Ineffective military and diplomatic responses to terrorism breeds more terrorism. Humanitarian aid to people in countries where the government has sworn to kill us all creates a false impression in their minds that we are soft and susceptible, that they can kill us and get away with it.
No one disputes that Afghanistan as well as some other mid-eastern countries are centers of terrorist training. This has to stop, and the only way to stop it seems to be military force. I argued prior to the Gulf War that sanctions would be effective in driving Iraq out of Kuwait. I was wrong--I am, as it happens, the only commentator on world events who has ever been wrong about anything.
Sanctions have been repeatedly proven to be an ineffective tool for altering the behavior of regimes that support terrorism. They haven't worked in Afghanistan and they haven't worked in Iraq, to name just two cases. If they didn't work before, they probably won't work now.
Nor will token military responses. Firing a few cruise missiles from a safe distance is not going to solve these people. Getting up close and personal with them will.
Despite the promptings of my hindbrain, I am not advocating carpet bombing everything from the Pillars of Hercules to the Hindu Kush. But I am advocating pretty much exactly what the United States seems to be doing: gathering international support for a (hopefully multi-national) force that will have the power to act with excessive force against any state known to be harbouring, aiding or abetting terrorism, and who are demonstrably unresponsive to non-military measures.
The logical end of this advice, I'm afraid, is military occupation of Afghanistan, probably Pakistan, and possibly other places as well. If such an occupation is followed by a "Marshall Plan" of rebuilding and education (especially for women) then I think it would be fully justified, and morally correct.
Doing something like this will be enormously costly. But the world is too small for people who think that their ideology gives them the right to kill people who simply disagree with them. Osama bin Laden, to take a non-random example, developed his hatred for the United States because of American defilement of the Arabian peninsula during the Gulf War, which was fought in defense of several Arab states against another Arab state.
bin Laden was not enraged by American funding of his compatriots in Afghanistan in their war against the Russians. He wasn't driven into a murderous frenzy of foot-stamping and childish hysterics by American support for Nigaraguan terrorists fifteen years ago. He hates America because it is a living embodiement of the values he despises: secularism, liberalism, freedom, and the open-heartedness and generosity that leads Americans to give hundreds of millions of dollars to aid people who would love to destroy them.