Yglesias worries about "catastrophic success in Gaza":
...something you need to look at here is the risk that weakening Hamas will only lead to the rise of more extreme groups. The high level of power that Hamas had achieved as of last week was, after all, precisely the result of a deliberate Israeli campaign to weaken Fatah. The hope was that this would bring some more accommodationist Palestinians to the fore, but instead the reverse happened. And now that Israel is going about trying the same thing with Hamas, one needs to worry that Hamas will be displaced by Salafist groups who think Hamas is too weak-kneed.