Yet some in Israel are pressuring the government to return a harsh response. Danny Ayalon has warned that "there is a heavy price for terrorism." Prime Minister Netanyahu echoed the sentiment but noted that he does not wish for an escalation.
For those who study bargaining in international relations, the key variable in this latest bout between Israel and Hamas is the intention of both actors. Rationally, neither Israel or Hamas have any interest in Operation Cast Lead II. Israel cannot afford such a war, neither economically nor politically. Hamas would also face similar costs, especially as PA-Hamas reconciliation efforts are underway. Hamas would be blamed for instigating chaos on the border of Egypt, whose security remains critical though stable. It may also face higher levels of criticism for using violent means, in contrast to the largely non-violent resistance of Egypt and Tunisia.
Yet in the dog-eat-dog world of the Middle East, it's better to be safe than sorry. This is why Israel is conditioning a cease-fire on a costly signal from Hamas. Stopping rocket and mortar attacks would demonstrate clearly that Hamas is serious. The problem is that this demand is at the very outer edge of Hamas' bargaining range, and might be outside it. Stopping the rockets would be a wise choice, but it's unclear if doing so would constitute "backing down" in the eyes of Gazans and in Israel's eyes as well, an unacceptable cost to Hamas.
But Hamas' two statements today are costly signals in and of themselves. If Hamas' objective were to draw Israel into a war in Gaza, de-escalation would be completely against its interests. By recognizing these signals, Israel can save itself the costs of an invasion, and move quickly towards a cease fire which would save Israeli lives.