Until 9/11 the USA had very little involvement in Afghanistan. After WW II there had developed what was called the Cold War between the democracies led by USA and the communist nations led by USSR which in turn was led by Russia. Basically with the Cold War, the Soviets and us were battling for world supremacy by meddling in the affairs of every one of the 200 odd nations of our planet, trying to get them not to become democratic or communist, but to support the democratic or communist side. It was easier for US foreign policy to get some dictator to help us, than to get a democracy to help out, so during the Cold War, the USA helped support a lot of cruel dictatorships. The people of those countries remember the generations of torture by the dictators supported by the US, so that is fueling a lot of the resentment today that provides recruits for the terrorists.

So when the Soviets invaded Afghanistan, the USA did not care a damn about Afghanistan, only that if the Soviets won, this would mean another notch in their belt score of how much of the world was under their domination, so the CIA gave covert aid to the Afghanistan rebellion, of which one of the leaders was this guy by the name of bin Laden, who was originally a Saudi millionaire, who got kicked out of his home country because he was such a trouble maker.

Eventually the rebels caused the Russians to withdraw from Afghanistan. They had help from CIA, but they did most of the work themselves. At the conclusion they said “We can bring down an Empire” (they thought of kicking Russia out of their country as the same as eliminating Russia) “Let’s do USA next.”

So in February 1998, bin Laden formerly declared war on USA, and his organization, al Quada, began a series of attacks on US facilities around the world, such as embassy buildings, and there was the US Cole warship. 9/11 was his first attack on US soil. Many more are planned.

Check my answer to this question, where I give links to estimates that they are about 2 years away from using WMD in a future attack on the USA. There’s other intelligence chatter that among their targets they are inspired by Columbine & VA Tech, and an attack on a school in Russia … they want to wipe out a few US schools.

http://answers.yahoo.com/question/index;_ylt=AvzeSUGRZPc63UvNTBMTtIPty6IX;_ylv=3?qid=20070717120014AAPALa1

After 9-11, it was figured out that bin Laden had engineered that, as part of his jihad against America. You can read his letter to Americans as to why he is fighting us here. (warning, the guy is a religious nut case)

http://observer.guardian.co.uk/worldview/story/0,,845725,00.html

Anyhow, at the time he was living in Afghanistan.

The USA demanded that Afghanistan turn him over to US justice. Afghanistan refused to turn over their hero to the USA, so the US declared war on Afghanistan and went in there to try to capture him. So far he has eluded US capture.