In its defence, Israeli spokespeople have claimed that the attack was a response to 'more than 100 rockets being fired in the previous 72 hours' (or some iteration thereof; you'll be hearing versions of this claim incessantly for the next few days). True or not, this aggregate misleads: it doesn't mention Israel's attacks over the same time period, of course, still less Israel's decades long occupation, which can only be sustained with constant low-level and periodic escalations of violence of the kind we're seeing now. But more narrowly: it conceals the fact that, prior to Israel's attack, Hamas and other Palestinian factions had offered, and largely adhered to, an informal truce.
Here, as best as I can gather from news sources, is the accurate chronology, focusing on Palestinian rockets only:
12 Nov: Palestinian militant groups announce that they've agreed to adhere to a truce, should Israel halt its operations. Islamic Jihad: 'The ball is in Israel's court'. There was 'no immediate response' from Israel, although Israeli Defence Minister Ehud Barak struck a belligerent tone with reporters, declaring: "The matter has definitely not ended". While Hamas took part in some of the missile launches at the weekend, by Monday it had stopped, 'suggesting it was looking to step back from the brink'. But already, Netanyahu had convened foreign ambassadors to prepare the diplomatic ground for an escalation.
12 Nov: According to the Israeli military, 12 rockets were fired on Nov 12; however Israel apparently later revised this number down to 6 rockets. This was clearly a 'significant drop' from the previous days: given that Al Jazeera reports that 115 rockets had been fired since Nov 10 (The Israeli military's estimate was 119, though this may have been before they revised down the 12 Nov figure). The rockets on 12 Nov were claimed not by Hamas but by smaller groups.
13 Nov: By 8am GMT, only 1 rocket had reportedly struck Israel. Israel, however, struck 3 targets in Gaza in the early hours of Tuesday (no casualties). [Al Jazeera] Two more rockets were fired into Israel in the afternoon. I couldn't find reference to any others. Israel and Hamas reportedly agreed a tacit truce, mediated by Egypt. Likud MK Benny Begin: "This round of firing appears to have ended".
14 Nov: Four rocket strikes reported.
14 Nov: Israel launches major attack, assassinating Jabari and striking over 20 locations across Gaza. The attack is still continuing. BBC, Reuters, the Jerusalem Post, the Guardian and Ynet all report that Israel's strike broke a lull in the fighting, during which rocket attacked had 'trickled down to a small number' (Jerusalem Post). As the International Crisis Group's Nathan Thrall puts it, 'this thing started after people were already talking about a ceasefire. The front page of Haaretz this morning was talking about a ceasefire and there was a lull at four in the afternoon when Jabari’s car was hit.'
So: Israel was offered a truce; didn't respond; then tacitly agreed to a lull, which appeared to be working, until Israel shattered it with a massive escalation; in self-defence.
Past data suggests that Palestinian rocket fire largely follows rather than provokes Israeli violence, and that, once a lull or truce has been agreed, Israel overwhelmingly kills first. This latest escalation, which may expand still further, appears to have followed the same pattern.
'Hours before Hamas strongman Ahmed Jabari was assassinated, he received the draft of a permanent truce agreement with Israel, which included mechanisms for maintaining the ceasefire in the case of a flare-up between Israel and the factions in the Gaza Strip. This, according to Israeli peace activist Gershon Baskin, who helped mediate between Israel and Hamas in the deal to release Gilad Shalit and has since then maintained a relationship with Hamas leaders...
Baskin told Haaretz on Thursday that senior officials in Israel knew about his contacts with Hamas and Egyptian intelligence aimed at formulating the permanent truce, but nevertheless approved the assassination.
“I think that they have made a strategic mistake," Baskin said, an error "which will cost the lives of quite a number of innocent people on both sides."
"This blood could have been spared. Those who made the decision must be judged by the voters, but to my regret they will get more votes because of this,” he added.
“He was in line to die, not an angel and not a righteous man of peace,” Baskin said of Jabari and of his feelings in the wake of the killing, “but his assassination also killed the possibility of achieving a truce and also the Egyptian mediators’ ability to function'.
Elsewhere, Baskin described the decision to assassinate Jabari as 'total insanity':
'Jaabri was behind enforcing all of the recent ceasefire agreements. He sent his troops out to stop the rockets and was prepared to reach a long term ceasefire. Jaabri was also the main interlocutor of the Egyptian intelligence service in reaching ceasefire understandings. Now who are they supposed to talk to? Who can expect the Egyptians to continue to mitigate our relationship with Gaza? Now the government and people of Israel will face a massive barrage of rockets and they bought the entrance card to Cast Lead II.'