There are many gaps in the story of Rabin’s assassination. But we can reliably fill them from the context. Israeli ruling establishment has a history of political assassinations, including Arlozoroff, the Season, and most likely the Kahanes and Zeevi. Assassinating Rabin won’t be outrageous. The establishment also has a documented history of blatant disregard for the law, such as Beilin-Peres negotiations with the PLO in Cairo before Rabin’s elections. Beilin and Peres are heavily invested in the peace process, and one more “victim of the peace process” was not a high price for them to pay. Both hated Rabin and numbered many grievances against him.
The two conspiracies were running concurrently. One was a normal Shin-Bet’s provocation against the right wing, in line with the subsequent framing of Goldstein, the purported Kahane Chai’s planning of the attack on Arab school, etc. Shin-Bet’s agent Champagnya worked in Hebron for years, and Yigal Amir was just one of his targets. Shin-Bet aimed at framing the right, not killing Rabin. So Amir, unknown to himself, was shooting blanks at Rabin. Shin-Bet infiltrated Amir into the sterile area of the highest security and warned the guards to stay away from Rabin to give Amir, a lame shooter, clear shot. That much we see on the video: Rabin’s guards step when Amir draws his gun. The shooting was theatrically staged after the immense peace show. It was planned in the sterile area rather than in the square so that no one stops Amir. Given Amir’s lack of relevant skills, that was an important consideration: he could not shoot Rabin from the crowd where many people would have stopped him. Shin Bet, accordingly, placed video operators near the scene to have evidence against Amir, thus the Keppler’s video. To retain credibility, the video has to be amateurish. Rabin was likely aware of the plot because on the video he looks at Amir seemingly quietly, without gesticulation. The Shin-Bet’s plot was going on for years. Champagnya spent much time with Amir and conservatives.
A big change came about shortly before the peace rally. Rabin publicly refused the concessions to Arabs and called for annexing the West Bank. It seems that he entered one of his hysterical mood swings. It became paramount for the Peres-Beilin group to get rid of Rabin. Planning the removal of Rabin - at that stage, not necessarily by murder - they came to know of Shin-Bet’s provocation plot, an insignificant operation among many similar ones. At that point, Peres or Beilin instructed Shin-Bet to move fast forward with the fake assassination, but also planned a follow-up: the real assassination of Rabin in his car. Although Shin-Bet was profoundly leftist and both Peres and Beilin had many appointees there, the security service undoubtedly knew nothing of the planned real assassination. Rabin was probably killed by a guard who worked for Peres. Rabin’s own guard was killed in the ensuing skirmish, and honorably buried a few days later after “committing suicide.”
Now Shin-Bet realized that the Peres-Beilin group framed it. The secret of Champagnya could not be kept for long and as soon as it came out, Shin-Bet was implicated in Rabin’s murder. That’s no small thing: a Shin-Bet agent convinced a right-winger to shoot Rabin. That smacks of a putsch. So Shin-Bet released the Keppler video to prove that Amir didn’t kill Rabin. Shin-Bet didn’t want to take a crash course with Peres and Beilin, and didn’t dispute the official version of Amir assassinating Rabin, but secured its own back by proving that Amir didn’t kill Rabin.