This week, the Hamas rulers of Gaza chose to abruptly shatter the fragile framework of assumptions which have governed relations between Israel and Gaza since the conclusion of Operation Cast Lead in early 2009. By taking responsibility for the launch of a barrage of Kassam rockets into the Negev, Hamas essentially announced the birth of a new phase in its long war of attrition with Israel.Operation Cast Lead purchased a period of relative quiet for Israel, through the imposition of deterrence upon Hamas-controlled Gaza. The movement, however, has now indicated that it considers that period to be at an end. What led it to this decision, and what may it portend? The Arab upheavals of 2011 posed particular dilemmas for Hamas and have produced significant changes in the balance of power within the movement. These changes underlie the current decision toward greater militancy in Gaza.Hamas can be considered both a winner and a loser from the Arab Spring. The Hamas leadership in Gaza and in particular the leaders of the armed wing, the Kassam Brigades, however, have derived only benefit from the changes.The movement’s external leadership, formerly centered in Damascus, has now scattered across the region.Hamas’s supposed leader, Khaled Mashaal, is in Doha, Qatar. His main rival, Moussa Abu Marzouk, is in Cairo.Other significant former Hamas residents of Damascus are now as far afield as Istanbul and Khartoum. One important Mashaal rival and advocate of armed militancy, Imad Alami, has taken up residence in Gaza.A veiled power struggle between the Gaza leaders and Mashaal has resulted. Each side holds to a particular preferred strategy which, while presented in terms of principle, would serve to maximize its own power and influence.Mashaal’s power has been much compromised by the disappearance of the Damascus base and the reduction of Iranian funding as a result of the failure to back Syrian President Bashar Assad. His preferred strategy for a return to relevance has been to push for reconciliation with the Palestinian Authority in the hope of achieving a political triumph for Hamas.The Gaza leadership understands that this direction would require reconciliation with the Ramallah-based PA, and therefore the ceding of their independent power base in the Gaza Strip.They advocate a rival strategy of holding on to “fortress Gaza,” maintaining links both with Iran and with the growing Muslim Brotherhood power in Egypt and thus enabling Hamas to play a central role in a new era of expected ongoing confrontation between Israel and an Egypt led by Hamas’s natural allies in the Muslim Brotherhood.In recent internal elections in Hamas, the Gaza leaders scored significant gains. Very few Mashaal-associated figures in the strip attained positions on the district shura councils, the Gaza shura council and the 15-member Gaza Political Bureau. Senior figures within the Kassam Brigades, such as Ahmed Jabari and Marwan Issa, meanwhile, were elected to the Gaza Political Bureau.Mashaal’s control over the budget of the Kassam Brigades is reported to have been removed.Gaza-based leaders have consequently felt able to simply ignore his supposed reconciliation agreement with Mahmoud Abbas, signed in Doha in February.Despite a flurry of recent media reports suggesting that the Gaza leadership had begun moves to help facilitate elections, nothing concrete has happened. Informed sources suggest that the talks on reconciliation have hit stalemate again. Simply put, giving up tangible power isn’t on the agenda of the ascendant Gaza Hamas leaders.The Iranians appear to be firmly backing the Gaza leaders and their strategy of confrontation.Fatah leaders have in fact alleged that the Gaza Hamas leadership was paid by Iran to prevent reconciliation.The Iranians are interested in tangible geographical areas from which to exert proxy military pressure on Israel. They have little use or interest for long political campaigns in which the Palestinians debate and argue over their preferred path. They appear for now at least to have gotten what they wanted.So a confident, militarized Hamas leadership in Gaza has retained the support of Iran. It is looking forward to a new era of militancy, in which it will maintain a direct land link to Egypt, where it expects its fellow Muslim Brothers to soon be in control.This will open up new possibilities in which, far from being under Israeli siege, Gaza Hamas hopes to itself form an advance element in a siege to be imposed upon Israel.The first confident shots in this new phase were fired this week.The fact that the Hamas Gaza leadership appears to have maintained the Iranian link while keeping its ties to the Muslim Brothers in Cairo should concern Israeli planners.It should serve to dispel any easy assumption that Shia and Sunni Islamists will continue indefinitely to tear one another apart, conveniently leaving Israel to enjoy the role of spectator.It should also be remembered that on at least one occasion in the past (in 1956), war between Egypt and Israel became inevitable as a result of a process begun by terrorist activity emerging from Gaza.The lull in conflict between Israel and Hamas-controlled Gaza was made possible because of Israel’s imposition of a balance of terror in Operation Cast Lead. The rise of the Muslim Brothers in Egypt and the decline of the Hamas external leadership have reset this balance.The birth tremors of this new phase were felt in southern Israel this week.