It may be that such measures are designed to demonstrate a credible commitment to a military response. In the wake of numerous operations and airstrikes in Gaza over the past decade, Israel needs to do more and more to show that this time it is in fact serious. It is possible that the severity of Israel's preparations for war are designed as a signal to scare Hamas into reducing rocket fire as part of an Egypt-brokered agreement. At the same time, they may be a signal based on Israel's actual intentions to invade the Gaza Strip.
At the center of the decision-making process in this latest flare-up in violence is Israel's Prime Minister, Benjamin Netanyahu. After calling for early elections, the Prime Minister is in a precarious position. His Likud party's alliance with the Yisrael Beiteinu party is expected to do well, but not win by a landslide. In addition, centrist and leftist parties in the Knesset are beginning to gain traction. While the leaders of these parties support, in principle, some armed intervention into Gaza, they are a liability for the Prime Minister and could quickly balance against him politically by criticizing any mistakes the government makes during the execution of a potential war. Netanyahu would know this effect well, given that he used it back in late 2008-early 2009 to degrade support for then-PM Tzipi Livni and the Kadima party. In this regard, it may be the case that in late 2012, the tables will turn.
In addition, the Israeli public has been concerned with Netanyahu's apparent support for Republican U.S. presidential candidate Mitt Romney. Israelis, while not resounding supporters of the Obama administration's Israel policy, fear that Netanyahu is unnecessarily distancing himself and Israel from the United States. Given that a Middle East war is not exactly line one of the Obama administration's foreign policy agenda, invading Gaza could be seen, in the medium-to-long term, as a policy which only exacerbates these differences. As many analysts have pointed out (Here, here, and here, for example), Obama is unlikely to seek "revenge" against Netanyahu. At the same time, Israelis may not want to take the risk of further alienating the administration.
At the same time, the severity of the situation in Israel's south may very well force a response by the Prime Minister. He likely will conceptualize this response in the short term, consistent historically with Israeli foreign policy decision-making. While the wisdom of an armed invasion of Gaza is very much in question given the nature of Hamas, the state of the Arab World, international public opinion, and an uncertain U.S. response, there can be little doubt that the situation requires a response. While the Iron Dome missile system has intercepted some rockets it has failed to hold back political pressure. At the same time, Israel would be well within its rights as a sovereign state to act in its self defense with a kinetic response to rockets.
In addition, PM Netanyahu might calculate that the Obama administration is also seeking to repair ties with Israel. Or more likely, he might calculate that the need to defend Israel's short term interests outweighs any cost it will have to pay in terms of a hit to its political capital with the United States.
In the Knesset, Netanyahu may suffer in the long term, but may be thinking in the short term. The long-term risk of political opposition may be worth it to the Prime Minister for the short-term rally-around-the-flag effect.
Ultimately, the rapid escalation of the situation is shortening the time-horizon in which the Prime Minister and his advisors are making decisions. The shorter the timeframe one considers, the more efficient armed intervention appears as an option. However, while Israel would be within its rights to respond militarily, its leaders should take a moment to plan for the medium and long term consequences of such an intervention.