When you think about how Aerys killed the Starks, too...he was a totally despicable, insane, not-worthy-to-be-king King. But Jaime had still sworn that oath. He should have detained the king. Somehow...I don't know how. It also wasn't necessary to kill Elia, Aegon and Rhaenys. Tokens of fealty...Tywin is seriously fucked up. I think that Aerys had to go and Rhaegar of course was marked for death by Robert because of the whole Lyanna situation, which we still don't know for certain the truth of.

I love your last paragraph...full circle indeed. And I love how Jaime sits with the white book knowing that the rest of his pages are free, clear and empty for him to fill out as he chooses...