However, there are a few slight loopholes that maybe can get Rabin out of being labeled a moser. I don't think they are much, but if in all fairness if we use the Rambam to condemn him let's look at what the Rambam has further to say.
I tried to translate the Rambam into English the best I can. I think it's accurate. I will just do the English, if someone wants the Hebrew I will scan it in and post it.
NOTE: THIS IS WHAT THE RAMBAM SAYS, IT DOESN'T MEAN THAT I AGREE OR DISAGREE OR THAT WE RULE ACCORDING TO THE RAMBAM.
Rambam, Sefer N'zikin, Hilchot Chovel uMazik, Perek Chet, Halacha Yud Bet:
I will just do the English, if someone wants the Hebrew I will scan it in and post it.
And so too anyone that distressed the public and continues to distress them, it is permitted to inform on him to the gentile authorities [so that they can] jail him, beat him, and fine him. But for the distress of a single individual it is forbidden to inform on him. And you cannot lose [confiscate] the informers money even though you can lose his life [kill him], since his money is suitable for his inheritors.
So let’s look at a few points:
1) The prohibition of informing is strictly to the gentile authorities. Now if he as PM of Israel goes and steals Jewish land and gives it away to the Arab terrorists, he isn’t informing on the Jews to the gentile authorities, he is stealing their land and giving it away. This is far fetched since an informer is someone who sells out Jewish lives or land to the gentiles. But maybe, just maybe, since he was the authorities, and he was Jewish, he first stole the land and then gave it away.
2) One might claim that all the land inside the State of Israel belongs to the State, and not to the individual. The people who founded the State can say they conquered it for themselves and allow you to live there. So they have the right to give it away. Again, far fetched but in the spirit of being “dan l’cav zezhut” let’s try to say that.
3) Further more, as the above Rambam says, “anyone that distressed the public and continues to distress them, it is permitted to inform on him to the gentile authorities [so that they can] jail him, beat him, and fine him.” Maybe, just maybe, Rabin can claim that the Jews on the land he wanted to give away were a distress to the public since they prevented peace. They don’t prevent peace, but maybe if he and the majority of the public felt that way, then they were distressing them. But that might not work because you may inform to the gentiles so that they can jail him, beat him, and fine him. Not so they can steal your land, unless you might say that is the permitted “fine”.
I never thought in my life that I would defend Rabin, but this was just for the fun of it, I think he is guilty of treason and should have been hung by the state of Israel’s judicial system. That someone else killed him, “v’chol hakodem zacha”, isn’t that what the Rambam says.
Just remember, we may not rule like the Rambam, if that’s the case, then Jewish law would not necessarily have allowed Amir to assassinate Rabin.
On this note, I wish him and his wife a hearty Mazal Tov and may they merit to have many more children and that he will be released from jail and made a national hero.