Naive observers frequently decry the apparent counter-productivity of extremist attacks. Don't the leaders of Hamas understand that every suicide bombing makes the Israelis that much more determined not to give the Palestinians a state? Don't they realize that the Israeli government will strike back even harder, and inflict even more suffering on the Palestinian people? Of course they do; they're not idiots. The Israeli response is exactly what they're counting on. More airstrikes, more repression, more poverty -- fewer opportunities for normal life to get in the way of the Great Struggle.The article goes on to discuss what Bin Laden wants (a topic I discussed a while back) and how he plans to go about getting it.
The cycle of violence may be vicious, but it is not pointless. Each round of strike-and-counterstrike makes the political center less tenable. The surviving radical leaders on each side energize their respective bases and cement their respective holds on power. The first round of the playoffs is always the two extremes against the center. Only after the center is vanquished will you meet your radical counterparts in the championship round.
I highly recommend reading the quiz. I'm not sure I agree with all of it, but it's interesting, entertaining, and relevant regardless.