This is a horror movie we've seen before. In the days following a US presidential contest, an Israeli government, about to face an election of its own, decides it can tolerate Hamas rocket-fire no longer. It hits back hard, determined to show the Israeli public that it is not sitting idle as a million of its citizens huddle in bomb shelters, their children unable to go to school, but that it is tough, ready to do whatever it takes to "restore deterrence". It will bring quiet to its southern towns by forcing Hamas to fear its wrath once more.
As it was after Barack Obama's election in 2008, so it is after his re-election in 2012. Four years ago, Operation Cast Lead was meant to root out "the infrastructure of terror" from Gaza, eradicating the Hamas threat. It did nothing of the sort, of course. Hamas was left in control, its threat merely postponed.
The evidence came in the last three months as missiles landed in Israel in greater numbers – 130 in the last few days alone. So once again, Israel decided to fight fire with fire, assassinating Hamas's senior military commander, Ahmed Ja'abari.
To understand how we got here, why tension turned into confrontation, and why at this moment, we need answers to two questions. First, why did Hamas allow Gaza once again to become a rocket launchpad, given that it has successfully imposed quiet during various periods since 2009? And why did Israel choose to get tough now, given that it has been willing to respond more mildly to such provocations in the past?
Start with Hamas. One reading assumes that Hamas was punished for its weakness, that it had proved itself no longer capable of reining in the more bellicose groups – Islamic Jihad and others – which operate on the territory it rules. The Haaretz editor, Aluf Benn, put that view starkly when he wrote that far from being a feared enemy, Israel's Osama bin Laden, Ja'abari was Israel's "subcontractor" in Gaza, charged with enforcing the de facto truce. When he stopped doing his job, he had to be removed: "The message was simple and clear: You failed – you're dead," wrote Benn, quoting a favourite saying of defence minister Ehud Barak: "In the Middle East there is no second chance for the weak."
But it's equally possible that this was no accidental escalation by Hamas, born of incompetence, but rather an act of strength by the Islamist movement. A senior Israeli official told me that Israel had long been aware of Hamas's burgeoning military capacity, its hoard of rockets growing – before Wednesday – to some 11,000, closing on the 15,000-strong arsenal amassed by Hezbollah on the eve of 2006's Lebanon war. Much of this arms supply had come from newly lawless Libya – a "goldmine" says the official – the rest from Iran, before relations between Tehran and Hamas cooled. (Iran was angered when Gaza's rulers broke from Tehran's number one ally, the Assad regime.) Hamas's arm is now more muscled and with a longer reach, as it graphically demonstrated last night, when rockets landed perilously close to Israel's central city, Tel Aviv – the first missiles to do so since the Gulf war of 1991.
But Hamas's new strength is diplomatic, as well as military. The Arab revolutions have redrawn the regional map, much of it in Hamas's favour. Once a pariah, Hamas now sees its own movement, the Muslim Brotherhood, ruling Egypt. Where Hosni Mubarak played broker between Israel and Gaza, often seeking to stay Hamas's hand, Cairo's new rulers feel a grassroots pressure to stand as the ally of Hamas. Witness the Egyptian president's swift despatch of his prime minister to visit Gaza on Friday.
What's more, the Gaza-based leadership has been engaged in a power struggle with the Hamas politburo outside the Strip. Taking the fight to Israel, becoming "the tip of the spear," as analyst Hussein Ibish puts it, is Gaza-based Hamas's way of asserting its pre-eminence.
What, though, of that second question: why did Israel hit back now? The Hebrew press immediately assumed the key date was political, not military: 22 January, when Israelis go to the polls. There are plenty of precedents for outgoing governments taking military action, hoping to create a wave of national unity that will carry them to victory: Cast Lead itself fits that pattern. Binyamin Netanyahu may well have wanted to push aside his Labor rival and prevent his predecessor, Ehud Olmert, making a planned comeback – forcing both to fall into line as patriotic cheerleaders. Similarly, Barak found a way to remind voters of his supposed indispensability.
Israeli officials deny any such thing, arguing that Netanyahu is too seasoned a pro to take such a high risk. He knows military adventures can backfire, and when they do, voters turn on the men who gave the orders. If Tel Aviv remains under attack, he will be in severe danger.
The risks go far beyond the small matter of Netanyahu's career. If Cairo translates its solidarity with Hamas into concrete action, Israel's post-1979 peace with Egypt will be imperilled. Since no one else is about to take over in Gaza, Hamas will remain in charge, very possibly strengthened – all the more so if the Fatah-dominated Palestinian Authority is seen to fail in its nonviolent attempt to win quasi-statehood at the UN general assembly.
Above all, the pain and anguish inflicted by yet another round of civilian deaths and injury will sow hatred in the hearts of another generation, who will grow up bent on revenge and yet more bloodshed. This keeps happening, decade after decade, for one simple reason: there can be no military solution to the Israeli-Palestinian conflict. Both sides will say the action they have taken is necessary. But it will solve nothing.
Jonathan Freedland writes a weekly column for the Guardian. He is also a regular contributor to the New York Times and the New York Review of Books.