JERUSALEM — The current conflict between Hamas and Israel is the result of the Palestinian Islamist movement overplaying its hand in an attempt to rewrite the rules of engagement between itself and Israel.

Hamas's miscalculation of the balance of forces between itself and Israel has now brought the Israel Defense Forces to the brink of a renewed ground operation in the Gaza Strip. If this is to be avoided, much depends on Western pressure on Hamas's allies, above all Egypt, so that they in turn may press the movement to accept a renewed ceasefire.

Hamas overreached in this conflict because it believed that its strategic position had been dramatically bolstered by recent events. Tactically, Israel's apparent willingness to tolerate a gradually increasing volume of rocket fire on communities in the western Negev and then beyond it -- in Beersheva, Ashkelon and Ashdod -- caused Hamas to assume that Israel could be further pressured into ceasing or significantly reducing its activities along the "security perimeter" west of the border fence, where the IDF operates to prevent tunnel digging and roadside bombings.  

In the early period following Operation Cast Lead, Israel's last offensive in Gaza, Hamas at times acted to prevent rocket fire on Israeli communities by the rival Palestinian Islamic Jihad movement, or one of the smaller Salafi groups operating in the region. The movement did this for pragmatic reasons -- it needed time to recover and rebuild from the effects of Cast Lead.

For obvious reasons, however, this situation was deeply uncomfortable for Hamas, which regards itself as being engaged in a long fight to the death with the Jewish state. In the course of 2012, it gradually divested itself of this approach. Fewer restrictions were placed on other organizations. Hamas itself began once more to openly join the fight against Israel. The number of rockets launched correspondingly increased.

In the course of 2012, prior to the outbreak of the current round of fighting, over 700 rockets were launched at Israel, the highest number since 2009. The final straw came with the Kornet missile attack on an IDF jeep patrol on Nov. 10, wounding four Israeli soldiers.

Hamas overestimated Israel's desire to avoid conflict. The assassination of Hamas military commander Ahmad al-Jaabari and the round of fighting now under way followed.

Strategically, Hamas has been deeply encouraged by the astonishing advances made by Sunni Islamism across the region. In Egypt and Tunisia, Hamas's fellow Muslim Brothers are now in power. In Syria, Sunni Islamists are at the forefront of the insurgency against President Bashar al-Assad's regime. And the Emir of Muslim Brotherhood-supporting Qatar recently visited Gaza, pledging a gift of $400 million.

The movement is right to be encouraged. Indeed, it may in retrospect be seen as the initiator of this process. The practical result of the 2011 "Arab Spring" has been the replacement of decrepit Arab nationalist regimes by Islamist ones. This began not in Tunisia in 2011, but in Gaza in 2007 -- when Hamas defeated and drove out the forces of Fatah and the Palestinian Authority.

So with the wind of history at its back, and with its ideological confreres now in power to its south in Cairo, Hamas felt able to push forward with the next chapter of its long, existential war against Israel.

How is it working out? From Hamas's perspective, not so well. The Palestinian Islamist movement has been tripped up by a number of complications.

The first and most obvious of these is the extent of the Israeli response. Israel, like Hamas, has noted the rise of Sunni Islamism across the region. It regards itself as engaged in a long war of attrition against the local representatives of this trend, which are committed to its destruction.

Jerusalem further considers that Hamas can be deterred, at least temporarily. Hence, the appropriate response to Hamas's inevitable, incremental attempts to advance against Israel should be periodic, short, sharp shocks in which Israel reminds the Islamist rulers of Gaza of the true balance of power between them. 

Secondly, Hamas's Islamist allies are turning out to be less reliable than had been hoped for. Egypt's rulers may be the ideological twins of Hamas, but Cairo cannot afford -- at least at this stage -- to unduly antagonize the West. The annual aid package of $2 billion from the United States, the $6.3 billion pledge from the European Union, and the $4.5 million loan from the International Monetary Fund would be placed in question by a policy of all-out support for Hamas missiles aimed at Israeli civilian targets.

As a result, Egypt and its Islamist allies are reportedly trying to persuade Hamas to accept a ceasefire. But Hamas's requirements are still astronomically high: It is demanding an internationally guaranteed Israeli commitment to cease targeted killings and the ending of all economic restrictions on Gaza.

These demands, of course, have no hope of being satisfied.

Nor, at this stage, can Hamas point to any great propaganda achievement that might enable it to claim that revenge had been taken for the killing of Jaabari. Yes, Hamas has succeeded in rocketing the Tel Aviv area, and in landing a missile in the vicinity of Jerusalem. The south of Israel is also under a constant rain of rockets and missiles. But Israel's Iron Dome missile defense system, and its early warning systems are preventing extensive loss of life.

In Gaza itself, meanwhile, the Israel Air Force is working its way down a list of quality infrastructure and human targets, which long and painstaking intelligence work has made possible. Simply put, the damage Israel is doing to Hamas is radically greater than the damage Hamas is doing to Israel.

All this means that Hamas, at the present time, apparently sees no feasible way out of the conflict other than continuing the fighting. The key question now is whether its continued refusal to negotiate a renewed ceasefire will make an Israeli ground invasion into Gaza inevitable.

Israel would undoubtedly prefer to avoid a major ground operation, which would inevitably cost many lives on both sides and cause significant diplomatic fallout. Such considerations matter less to Hamas: If the experiences of Operation Cast Lead and the 2006 Lebanon war are any guide, Islamist organizations' relative indifference to the fate of the civilians under their control can work to their advantage at such a juncture. Hamas calibrates loss of individual life differently than Israel and from a diplomatic point of view could gain from enhancing its "resistance" image as a result of a bloody battle in Gaza. 

And since Israel has made clear it does not intend to bring down the Hamas-led authority in Gaza, the movement need not fear that an Israeli ground incursion would lead to its fall from power.  

But while Hamas may prefer continued defiance, its allies are required to take a broader view. As mentioned above, the Islamist governments and fellow travelers in Egypt, Qatar and Turkey have not backed Hamas unconditionally, because these countries are in different ways allied with or dependent on the West. The key question now is whether the West, using its own pressure on these countries -- and above all on Egypt -- can cause them to induce Hamas to accept a renewed ceasefire. If this does not happen, then an Israeli ground operation becomes a near-inevitability.

The conclusion of this conflict is not in doubt: A ground operation will end with a renewed tacit ceasefire and a new period of quiet. It would be better if this could be achieved without the deaths a ground attack would entail. The responsibility for ensuring this now lies with those countries that have sway over Hamas's allies across the Arab world.