Prof. Jeff Sikkenga of Ashland University provides a good answer to Andrew’s query on NoLeftTurns:
Why did Israel kill Sheikh Yassin, the founder of HAMAS? Obviously, they know this ups the stakes even more in the conflict with the most radical elements among the Palestinians.
So why? I don’t think it’s a coincidence that the action follows immediately on the heels of Benjamin Netanyahu’s agreement to give provisional support for the phased withdrawal from Gaza and parts of the West Bank in conjunction with continued building of Israel’s security barrier. This means that the plan will very likely make it through Sharon’s cabinet and become a reality.
If so, Israel knows that it must withdraw settlers on terms of strength, or its pullout will be trumpeted by its enemies as a sign of weakness, as happened with the military withdrawal from southern Lebanon. So look for even more audacious strikes in the weeks ahead against HAMAS, Islamic Jihad, and the Al Aksa Brigades, especially the kind of strikes that can help certain elements within the PA to take more authority once Israel has withdrawn and given up day-to-day control over Gaza and most of the West Bank.
Notwithstanding the revenge attacks to come, Israel really ius changing the security equation, and it looks like the Palestinians are in trouble.