But if Netanyahu and Barak are responsible for creating the immediate pretext for an attack on Gaza, they are also criminally negligent for failing to pursue an opportunity to secure a much longer truce with Hamas.
We now know, thanks to Israeli peace activist Gershon Baskin, that in the period leading up to Jabari's execution, Egypt had been working to secure a long-term truce between Israel and Hamas. Jabari was apparently eager to agree to it.
Baskin, who was intimately involved in the talks, was a credible conduit between Israel and Hamas because he had played a key role last year in getting Jabari to sign off on a prisoner exchange that led to the release of Israeli soldier Gilad Shalit. Baskin noted in the Haaretz newspaper that Jabari's assassination "killed the possibility of achieving a truce and also the Egyptian mediators' ability to function."
The peace activist had already met Barak to alert him to the truce, but it seems the defence minister and Netanyahu had more pressing concerns than ending the tensions between Israel and Hamas.
What could have been more important than finding a mechanism for saving lives, on both the Palestinian and Israeli sides? Baskin offers a clue: "Those who made the decision must be judged by the voters, but to my regret they will get more votes because of this."
It seems Israel's general election, due in January, was uppermost in the minds of Netanyahu and Barak.
A lesson learned by Israeli leaders over recent years, as Baskin notes, is that wars are vote-winners solely for the right wing. That should be clear to no one more than Netanyahu. He has twice before become prime minister on the back of wars waged by his more "moderate" political opponents as they faced elections.
Shimon Peres, a dove by no standard except a peculiar Israeli one, launched an attack on Lebanon, Operation Grapes of Wrath, that cost him the election in 1996. And centrists Ehud Olmert and Tzipi Livni again helped Netanyahu to victory by attacking Gaza in late 2008.
Israelis, it seems, prefer a leader who does not bother to wrap a velvet glove around his iron fist.
Netanyahu was already forging ahead in the polls before he minted Operation Pillar of Defence. But the electoral fortunes of Ehud Barak, sometimes described as Netanyahu's political Siamese twin and a military mentor to Netanyahu from their commando days together, have been looking grim indeed.
Barak desperately needed a military rather than a political campaign to boost his standing and get his renegade Independence party across the electoral threshold and into the Israeli parliament. It seems Netanyahu, thinking he had little to lose himself from an operation in Gaza, may have been willing to oblige.
Third Culprit: The Israeli Army
Israel's army has become addicted to two doctrines it calls the "deterrence principle" and its "qualitative military edge." Both are fancy ways of saying that, like some mafia heavy, the Israeli army wants to be sure it alone can "whack" its enemies. Deterrence, in Israeli parlance, does not refer to a balance of fear but Israel's exclusive right to use terror.
The amassing of rockets by Hamas, therefore, violates the Israeli army's own sense of propriety, just as Hizbullah's stockpiling does further north. Israel wants its neighbouring enemies to have no ability to resist its dictates.
Doubtless the army was only too ready to back Netanyahu and Barak's electioneering if it also provided an opportunity to clean out some of Hamas' rocket arsenal.
But there is another strategic reason why the Israeli army has been chomping at the bit to crack down on Hamas again.