In the past three months, these opposition organizations launched nearly 400 rockets into Israel. Despite being the most violent exchanges of fire since 2008, Israel responded moderately. No Hamas men were killed -- only militants from the opposition organizations. Israel's restraint reflects its changing strategy on Hamas. In this thinking, targeting Hamas would potentially increase the leverage of the more violent, less predictable opposition organizations, raising the prospects for chaos and for attacks against Israeli towns and civilians.

Hamas seems to have little interest in escalating with Israel, either. Previous escalations have cost the movement men and vital infrastructure, including weapons caches and smuggling tunnels. Over the past year, excepting of course this recent attack, Hamas did not actively participate in fighting, and negotiated with the opposition organizations to stop violence that could have dragged Gaza into self-perpetuating conflict. Hamas' conduct seems to reflect a new strategy of its own: no to initiating attacks against Israel; yes to checked retaliation and only if Israel attacks first. (Again, this recent attack was an exception.) Hamas even established a special unit to prevent members of the opposition organizations from shooting rockets into Israel. The Qūwat Dabt Al-Maydaan (Field Control Force) mandates the arrest or shooting of any militant who violates this order. Considering Hamas' own reputation of launching thousands of such rockets in the past decade, its new official measures to not just stop its own shelling of Israel but to aggressively deter others suggests that its leaders' understand that maintaining a calm border advances Hamas' goal of consolidating rule in Gaza.

Gaza opposition organizations have, unsurprisingly, criticized Hamas' abstention from fighting. This may explain Hamas' recent rocket attack: delivering a message to these organizations that Hamas remains committed to the armed struggle against Israel. Of course, the fact that this message involved shooting explosives into Israel says something about the nature of Hamas. Yet despite its active role in the recent fire, the movement worked to negotiate a ceasefire and has shown no interest in escalation. What's most worrying about Hamas' fire is that it indicates the growing influence of the opposition organizations over the movement's strategic decisions and their ability to drag it to use force against its strategy.

Egypt, for its part, shares the desire to prevent escalation. Violence between Israel and Hamas could well spark Palestinian solidarity protests on Egyptian streets and increase public pressure to cancel the peace treaty with Israel -- something the nascent post-Mubarak would probably prefer not to deal with right now.

Egypt is an important player here, and not just because they helped to negotiate the ceasefire. Hamas made its new home in Egypt, after its political leaders left Syria to protest the regime's violence there. To help Gaza's economy, Egypt reopened the Rafah Crossing, which Mubarak had closed in 2007. Because Hamas is dependent on Cairo's hospitality and support, it tries to refrain from potentially destabilizing actions, including a clash with Israel, that might displease Cairo. Egypt has come to play a greater role in maintaining tranquility over the past year. Its security services have helped moderate unofficial, indirect talks between Israeli and Hamas delegates. Egyptian mediation helped secure the exchange of Gilad Shalit, a Israeli soldier long held in Gaza, for 1,027 Palestinian prisoners in late 2011.