EXECUTIVE SUMMARY: The Israeli military offensive in Gaza reflects the assumption that Israel is in a protracted intractable conflict. It is unlikely that Israel can purge Hamas from Palestinian society, nor is a political solution likely to be achieved. Instead, Israel is acting in accordance with a "mowing the grass" strategy. After a period of military restraint, Israel is acting to severely punish Hamas for its aggressive behavior and degrade its military capabilities – aiming at achieving a period of quiet.

Hamas left Israel's government no choice but to order the Israel Defense Force (IDF) to start a land incursion. Hamas refused to accept the Israeli government's offer of "calm for calm," rejected the Egyptian cease-fire proposal and violated the humanitarian cease-fire initiated by the UN. It continuously fired over 10 days more than 1,500 missiles towards towns and cities of Israel, hoping to kill as many civilians as possible. Moreover, it uses tunnels in the attempt to kill Israeli civilians and/or kidnap them.

Israel's goal continues to be the establishment of a reality in which Israeli residents can live in safety without constant indiscriminate terror, while striking a significant blow to Hamas' terror infrastructure. The Israeli government wisely has defined limited political and military goals for this offensive, in accordance with what we call a "mowing the grass" strategy.

Israel's strategy in the twenty-first century against hostile non-state groups, such as Hamas, reflects the assumption that Israel finds itself in a protracted intractable conflict. The use of force in such a conflict is not intended to attain impossible political goals, but rather is a long-term strategy of attrition designed primarily to debilitate the enemy capabilities. Only after showing much restraint in its military responses, does Israel act forcefully to destroy the capabilities of its foes as much as possible, hoping that occasional large-scale operations also have a temporary deterrent effect in order to create periods of quiet along Israel's borders.

As the ground phase of "Operation Protective Edge" progresses, Israel must be realistic about what can be achieved. Destroying the terror tunnels along the fence around Gaza is an attainable military goal. In the process terrorists can be killed and a part of the terrorist infrastructure demolished. The Israeli ground advance might create unrest within the Hamas organization, causing some of its military leadership to move around and make mistakes that could result in better intelligence and opportunities for targeted killings from the air.

An expansion of the ground operation might exact an even higher price from Hamas. Continuous shelling of Israel by Hamas may inevitably lead to Israel's conquest of all of Gaza. Yet, the strategic calculus should always focus on cost-effectiveness.

Despite the calls from the political Right in Israel, the demise of Hamas rule in Gaza is not an attainable military objective. Hamas is well-rooted in Palestinian society, particularly in Gaza. A recent Pew poll shows 35 percent of the Palestinians view Hamas in a favorable way. Eradicating Hamas and the subsequent political engineering of Palestinian society is not something outsiders can do. Even if Hamas rule can be terminated, the alternatives are Israeli rule, the rule of more radical groups, or chaos. None are good options.

Similarly, calls from the Israeli Left for reaching a "political solution" are totally unrealistic. Hamas, Islamic Jihad and Salafist groups see Israel as a theological aberration, and despite reluctant acceptance of temporary cease-fires, reject any diplomatic course of action intended to solve the Israeli-Palestinian conflict. The fanatic commitment of these militias to a radical ideology and to a long-term strategy of violent resistance (muqawama), turn the situation into an intractable conflict.

As the rounds of violence with Hamas continue, the frustration with lack of clear military decision or with the absence of a peaceful resolution is understandable. Nevertheless, employing military force is useful in such limited small wars with no clear decision. Hamas needs to be punished for its aggressive behavior and reminded of the cost it must pay for continuing the violence against Israel. A period of calm can be achieved by destroying capabilities that are hard and expensive to rebuild. Buying time is a legitimate goal. Additionally in the current strategic situation Hamas is isolated, making the rebuilding of its military assets a longer process.

Moreover, other actors in this Middle East neighborhood are watching, and they also need a clear reminder that aggression against Israel is costly. Inaction would be perceived as weakness, harming deterrence and inviting aggression. Israel's greatest achievement in this conflict so far was its missile defense system, which allows the home front to maintain a great deal of normalcy. Israel has also signaled determination, by its readiness for ground operations, despite the potential casualties.

Those who forlornly ask "when is this going to end?" and use the cliché "cycle of violence," have psychological difficulties digesting the facts that there is no solution in sight and that the violent struggle against Hamas is not going to end any time soon (not as long as the enemy's basic ideological motivations remain intact). But still, important periods of quiet are attainable by military action, and this is what explains Israel's current offensive.

The Israeli approach described here is substantively different from current Western strategic thinking on dealing with non-state military challenges. Western thinking is solution-oriented. This explains part of the lack of understanding for what Israel is doing.

Against an implacable, well-entrenched, non-state enemy like the Hamas, Israel simply needs to "mow the grass" once in a while in order to degrade enemy capabilities. A war of attrition against Hamas is probably Israel's fate for the long term. Keeping the enemy off balance and reducing its capabilities requires Israeli military readiness and a willingness to use force intermittingly, while maintaining a healthy and resilient Israeli home front despite the protracted conflict.