The story is this: a bearded religious fanatic, convinced of the righteousness of his cause, hatches a plan to violently attack all those who stand in his cause's way. He attracts several like-minded recruits, who join for a variety of reasons, and carries out a string of successful, often bloody and destructive attacks, culminating in a symbolic attack on an American landmark that is remembered for a long time thereafter.
There are those who say it's difficult to get inside the mind of a terrorist, to understand what could possibly drive them to kill their fellow man. But if you sympathize with the story of radical abolitionist hero John Brown, whose story I just told you and whose attack on the Federal arsenal at Harper's Ferry occurred 150 years ago last week, you should find it rather easy. Brown was, after all, a terrorist... but one that, on the whole, most Americans agree with. (Southerners who still hold out in their opposition to Brown, substitute William Quantrill or John Mosby here. While both were official rebel army officers, their tactics were similar to Brown's.) Perhaps we can support Brown because history proved Brown right - the despicable institution of slavery would require widespread violence to bring down. Or perhaps it is because we know that slavery was a violent system, and using violence to bring it down was therefore justified. Or perhaps it's just because the model of non-violent resistance practiced by Gandhi and King simply hadn't been thought up yet.
But make no mistake - were Brown alive today, he'd be considered a terrorist. (So would Mosby and Quantrill.) So when we call someone a "terrorist," we'd do well to realize that they care about whatever cause they support in the same way John Brown cared about ending slavery, and that if we're to fight them, we might want to understand what that cause is, and why people care about it so much. This isn't to say that Brown was wrong, or that the Islamic extremists are right. It's just to say that the kind of passion terrorists have for their causes isn't so foreign to us after all.