Gaza operation that took the lives of 282 was planned 6 months ago

Please see this article from Barak Ravid in Ha'aretz for more info:
Disinformation, secrecy and lies: How the Gaza offensive came about

	Long-term preparation, careful gathering of information, secret discussions, operational deception and the misleading of the public - all these stood behind the Israel Defense Forces "Cast Lead" operation against Hamas targets in the Gaza Strip, which began Saturday morning. The disinformation effort, according to defense officials, took Hamas by surprise and served to significantly increase the number of its casualties in the strike. Sources in the defense establishment said Defense Minister Ehud Barak instructed the Israel Defense Forces to prepare for the operation over six months ago, even as Israel was beginning to negotiate a ceasefire agreement with Hamas. According to the sources, Barak maintained that although the lull would allow Hamas to prepare for a showdown with Israel, the Israeli army needed time to prepare, as well. Barak gave orders to carry out a comprehensive intelligence-gathering drive which sought to map out Hamas' security infrastructure, along with that of other militant organizations operating in the Strip. This intelligence-gathering effort brought back information about permanent bases, weapon silos, training camps, the homes of senior officials and coordinates for other facilities. The plan of action that was implemented in Operation Cast Lead remained only a blueprint until a month ago, when tensions soared after the IDF carried out an incursion into Gaza during the ceasefire to take out a tunnel which the army said was intended to facilitate an attack by Palestinian militants on IDF troops. On November 19, following dozens of Qassam rockets and mortar rounds which exploded on Israeli soil, the plan was brought for Barak's final approval. Last Thursday, on December 18, Prime Minister Ehud Olmert and the defense minister met at IDF headquarters in central Tel Aviv to approve the operation. However, they decided to put the mission on hold to see whether Hamas would hold its fire after the expiration of the ceasefire. They therefore put off bringing the plan for the cabinet's approval, but they did inform Foreign Minister Tzipi Livni of the developments. That night, in speaking to the media, sources in the Prime Minister's Bureau said that "if the shooting from Gaza continues, the showdown with Hamas would be inevitable." On the weekend, several ministers in Olmert's cabinet inveighed against him and against Barak for not retaliating for Hamas' Qassam launches. "This chatter would have made Entebe or the Six Day War impossible," Barak said in responding to the accusations. The cabinet was eventually convened on Wednesday, but the Prime Minister's Bureau misinformed the media in stating the discussion would revolve around global jihad. The ministers learned only that morning that the discussion would actually pertain to the operation in Gaza. In its summary announcement for the discussion, the Prime Minister's Bureau devoted one line to the situation in Gaza, compared to one whole page that concerned the outlawing of 35 Islamic organizations. What actually went on at the cabinet meeting was a five-hour discussion about the operation in which ministers were briefed about the various blueprints and plans of action. "It was a very detailed review," one minister said. The minister added: "Everyone fully understood what sort of period we were heading into and what sort of scenarios this could lead to. No one could say that he or she did not know what they were voting on." The minister also said that the discussion showed that the lessons of the Winograd Committee about the performance of decision-makers during the 2006 Second Lebanon War were "fully internalized." At the end of the discussion, the ministers unanimously voted in favor of the strike, leaving it for the prime minister, the defense minister and the foreign minister to work out the exact time. While Barak was working out the final details with the officers responsible for the operation, Livni went to Cairo to inform Egypt's president, Hosni Mubarak, that Israel had decided to strike at Hamas. In parallel, Israel continued to send out disinformation in announcing it would open the crossings to the Gaza Strip and that Olmert would decide whether to launch the strike following three more deliberations on Sunday - one day after the actual order to launch the operation was issued. "Hamas evacuated all its headquarter personnel after the cabinet meeting on Wednesday," one defense official said, "but the organization sent its people back in when they heard that everything was put on hold until Sunday." The final decision was made on Friday morning, when Barak met with Chief of Staff General Gabi Ashkenazi, the head of the Shin Bet Security Service Yuval Diskin and the head of the Military Intelligence Directorate, Amos Yadlin. Barak sat down with Olmert and Livni several hours later for a final meeting, in which the trio gave the air force its orders. On Friday night and on Saturday morning, opposition leaders and prominent political figures were informed about the impending strike, including Likud chairman Benjamin Netanyahu, Yisrael Beuiteinu's Avigdor Liebermen, Haim Oron from Meretz and President Shimon Peres, along with Knesset Speaker Dalia Itzik.