By the time Israel attacked the Yarmouk facility, Hamas had to assume that Israel knew of the weapons transfer to Gaza. Hamas then quickly agreed to an Egyptian-mediated ceasefire Oct. 25. When attacks against Israel began picking up again around Nov. 10 -- including an anti-tank attack on an Israeli military jeep claimed by the Popular Front for the Liberation of Palestine and several dozen more rocket attacks claimed by Palestinian Islamic Jihad and smaller Salafist-jihadist groups -- Hamas appeared more cautious, calling the main Gaza militant groups together on Nov. 12 to seek out another truce. By then, it was too late. They had already inadvertently provided the Israelis with the justification they needed to get public relations cover for their campaign to destroy Hamas' long-range rocket program.
On Nov. 14, Jabari was assassinated, and Hamas had to work under the assumption that Israel would do whatever it took to launch a comprehensive military campaign to eliminate the Fajr threat. It is at this point that Hamas likely resigned to a "use it or lose it" strategy and launched Fajr rockets toward Tel Aviv, knowing that they would be targeted anyway and potentially using the threat as leverage in an eventual attempt at another truce with Israel. A strong Hamas response would also boost Hamas' credibility among Palestinians. Hamas essentially tried to make the most out of an already difficult situation and will now likely work through Egypt to try to reach a truce to avoid an Israeli ground campaign in Gaza that could further undermine its authority in the territory.
In Tehran, Iranian officials are likely quite content with these developments. Iran needed a distraction from the conflict in Syria. It now has that, at least temporarily. Iran also needed to revise its relationship with Hamas and demonstrate that it retains leverage through militant groups in the Palestinian territories as part of its deterrence strategy against a potential strike on its nuclear program. Hamas decided in the past year that it was better off aligning itself with its ascendant parent organization, the Muslim Brotherhood, than remaining tethered to an ideological rival like Iran that was being put on the defensive in the region. Iran could still capture Hamas' attention through weapons sales, however, and may have even expected that Israel would detect the Fajr shipments.
The result is an Israeli military campaign in Gaza that places Hamas' credibility in question and could create more space for a group like the Palestinian Islamic Jihad, which has close ties to Iran. The conflict will also likely create tension in Hamas' relationship with the Muslim Brotherhood in Egypt, Jordan and Syria, since the Brotherhood, particularly in Egypt, is not prepared or willing to confront Israel beyond rhetoric and does not want to face the public backlash for not doing enough to defend the Palestinians from Israel Defense Forces. All in all, this may turn out to be a relatively low-cost, high payoff maneuver by Iran.