Switched over from the
Cersei? pregnant? thread as it seems to have more relevance here.
Cercei does also have her brain... which all Cercei hating aside, IS formiddable. her downfall is she lacks patience and the "long view" Tywin possessed.
"She does not lack for wits, but she has no judgment, and no patience" AFFC
She IS currently Lady Lannister, as well as being Queen Regent. With Jaime a sworn member of the Kingsguard, and Tyrion being a wanted criminal with a death warrant on his head, Cercei, as the next in line, is Lady of Casterly Rock. Kevan got nothing. iirc he has minor lands, but he's certainly not Lord Lannister.
I am the last one to say Cersei doesn't have a brain. She
absolutely does. I just think that her mentality, that of being somewhat narcissistic ("Cersei Lannister is indescribably beautiful," etc.) and very self-important, which I grant is only somewhat her fault (she
is Tywin Lannister's only daughter after all, and would have been raised to that form of thinking and self-image) has led her to make some epically poor choices. Namely the choosing of her small council who are nothing more than "yes men" parroting back to her what she wants to hear and telling her how smart she is, and the fact that she spurns alliances she actually needs (Tyrells) in order to stabilize and strengthen the kingdom. She lets her personal negative bias toward the Tyrells cloud her judgment regarding their usefulness, which I think demonstrates narrow-mindedness and a clear disregard for what would be best for the kingdom.
Having nearly finished my reread of AFFC, I can only reinforce my thoughts from earlier. I believe that her renowned beauty in great deal shaped and defined how she views herself. There is a particular quote of Maggy the Frog's that I believe really demonstrates this:
"Queen you shall be . . . until there comes another, younger and more beautiful, to cast you down and take all that you hold dear."
The 'younger and more beautiful' part I think is a key identifier in Cersei's problem. It states that yes, Cersei will lose her position as queen, which as Tywin Lannister's daughter is a position she would cling to dearly, and certainly something she holds dear. But it additionally states "take
all that you hold dear" which can be left open to interpretation. Without a doubt she values her children. Her grief for Joffery was genuine; her protective nature where Myrcella and Tommen are concerned is without question. It is also clear that she has, at least until recently, loved and needed her twin Jaime.
But as Cersei was raised by Lord Tywin, who knew his golden children were perfect, and took great pains to let the rest of the world know it too, she was raised with the knowledge that she was an unparalleled beauty, something that would most certainly shape and define her image of herself. So to lose her queen-ship to someone "younger and more beautiful" does not just suggest that she loses what goes along with being queen, but that she will lose a great deal more, and what could be worse than not only losing the position you worked so hard to attain and keep, but to in essence lose everything that defined you as you? So ultimately, it's not just her position or family, but her identity that's at stake.
I think that would be more than enough to screw with someone's head. My two cents.