Space aliens are controlling his mind

Bad oysters

He lost a bizarre sex bet with (Israeli Justice Minister) Tzipi Livni

Medical marijuana

He's reviewed the cases of each of the murderers he plans to release and they've all become born again Christians (or Jews?) in prison who will renounce all violence in the name of Islam or the Palestinian cause

We'll never know, at least not for 50 years or more when they declassify a ton of stuff so why guess

Elsewhere, Israeli journalists aired conspiracy theories that the release was part of a larger bargain for greater U.S. help on Iran:

.@DanWilliams @Bogie_Yaalon I have sneaky suspicion Israel agreed to free Palestinian terrorists+ renew talks in return for US help on Iran -- Amir Mizroch (@Amirmizroch) July 29, 2013

On a more serious note, Israeli Economic Minister Naftali Bennett, who opposed the release, warned, "In the past we freed a terrorist for a live soldier, later hundreds of terrorists for one live soldier, later terrorists for a dead soldier; and now -- a hundred terrorists for a process. We are showing the world that, for us, everything is negotiable."

But just as Israelis believe passionately that the prisoners are terrorists, Palestinians view them as heroic crusaders, and most see their release as essential to the renewal of talks. According to a recent Gallup poll, the prisoner release was the top precondition for peace negotiations for Palestinians, with 93 percent saying it should be a precondition and 99 percent saying it was a "top priority."

Palestinian Authority President Mahmoud Abbas had also refused to move forward without an agreement on the releases.

According to an account of the Israeli cabinet's decision from Haaretz, it was a painful decision for Netanyahu and the supporting ministers, but one they felt was a long-term boost for Israel on the international stage.

None of the ministers enjoyed voting in favor of a wholesale release of murderers of Jews. Some of the ministers said that Netanyahu hated every moment; he seemed to be suffering. But he, more than most of his colleagues, was very well aware of the high price that Israel would have paid in the international, legal, and economic arenas had the voting results been different.

"This moment is not easy for me. It is not easy for the ministers. It is not easy especially for the families, the bereaved families, whose heart I understand," Netanyahu said at the meeting. "But there are moments in which tough decisions must be made for the good of the country, and this is one of those moments."

The release also potentially paves the way for fewer restrictions on settlement construction, another contentious issue, later in the talks. By giving on prisoners, Haaretz writer Yossi Vertner noted, Netanyahu might have made it easier for the settlers in the long run.