The issue at hand after that bit of psychoanalysis on Cersei is whether she is a different character in Feast than she was in the first three books. While Cersei is able to outwit Ned Stark and Robert in GoT and seems to come across as a Machiavellian mastermind. It is my contention that Cersei was always an idiot. And that any perception of her as being astute doesn't last long into Clash. Cersei only looks clever when compared to Ned and Robert who both cheated off Hodor in order to get through high school.
Presented for the consideration of the midnight society:
Cersei is an Idiot:
“If it was Father who’d been taken captive, Jaime would not be sitting by idly, I promise you.”
Jaime would be battering his host to bloody bits against the walls of Riverrun, and the Others take their chances. He never did have any patience, no more than you, sweet sister. “Not all of us can be as bold as Jaime, but there are other ways to win wars. Harrenhal is strong and well situated.”
“And King’s Landing is not, as we both know perfectly well. While Father plays lion and fawn with the Stark boy, Renly marches up the roseroad. He could be at our gates any day now!”
“The city will not fall in a day. From Harrenhal it is a straight, swift march down the kingsroad. Renly will scarce have unlimbered his siege engines before Father takes him in the rear. His host will be the hammer, the city walls the anvil. it makes a lovely picture.”
Cersei’s green eyes bored into him, wary, yet hungry for the reassurance he was feeding her. “And if Robb Stark marches?”
“Harrenhal is close enough to the fords of the Trident so that Roose Bolton cannot bring the northern foot across to join with the Young Wolf’s horse. Stark cannot march on King’s Landing without taking Harrenhal first, and even with Bolton he is not strong enough to do that.” Tyrion
tried his most winning smile. “Meanwhile Father lives off the fat of the riverlands, while our uncle Stafford gathers fresh levies at the Rock.”
Cersei regarded him suspiciously. “How could you know all this? Did Father tell you his intentions when he sent you here?”
“No. I glanced at a map.”
A complete failure to grasp tactical and strategic implications of geography.
“Yes, yes,” the queen said impatiently, “but first we must stop this filth from spreading further. The council must issue an edict. Any man heard speaking of incest or calling Joff a bastard should lose his tongue for it.”
“A prudent measure,” said Grand Maester Pycelle, his chain of office clinking as he nodded.
“A folly,” sighed Tyrion. “When you tear out a man’s tongue, you are not proving him a liar, you’re only telling the world that you fear what he might say.”
“So what would you have us do?” his sister demanded.
“Very little. Let them whisper, they’ll grow bored with the tale soon enough. Any man with a thimble of sense will see it for a clumsy attempt to justify usurping the crown. Does Stannis offer proof? How could he, when it never happened?” Tyrion gave his sister his sweetest smile.
“That’s so,” she had to say. “Still.”
“Your Grace, your brother has the right of this.” Petyr Baelish steepled his fingers. “If we attempt to silence this talk, we only lend it credence. Better to treat it with contempt, like the pathetic lie it is. And meantime, fight fire with fire.”
Cersei gave him a measuring look. “What sort of fire?”
“A tale of somewhat the same nature, perhaps. But more easily believed. Lord Stannis has spent most of his marriage apart from his wife. Not that I fault him, I’d do the same were I married to Lady Selyse. Nonetheless, if we put it about that her daughter is baseborn and Stannis a cuckold, well... the smallfolk are always eager to believe the worst of their lords, particularly those as stern, sour, and prickly proud as Stannis Baratheon.”
“He has never been much loved, that’s true.” Cersei considered a moment. “So we pay him back in his own coin. Yes, I like this. Who can we name as Lady Selyse’s lover? She has two brothers, I believe. And one of her uncles has been with her on Dragonstone all this time...”
“Ser Axell Florent is her castellan.” Loath as Tyrion was to admit it, Littlefinger’s scheme had promise. Stannis had never been enamored of his wife, but he was bristly as a hedgehog where his honor was concerned and mistrustful by nature. If they could sow discord between him and his followers, it could only help their cause. “The child has the Florent ears, I’m told.”
Littlefinger gestured languidly. “A trade envoy from Lys once observed to me that Lord Stannis must love his daughter very well, since he’d erected hundreds of statues of her all along the walls of Dragonstone. ‘My lord’ I had to tell him, ‘those are gargoyles.”‘ He chuckled. “Ser Axell might serve for Shireen’s father, but in my experience, the more bizarre and shocking a tale the more apt it is to be repeated. Stannis keeps an especially grotesque fool, a lackwit with a tattooed face.”
Grand Maester Pycelle gaped at him, aghast. “Surely you do not mean to suggest that Lady Selyse would bring a fool into her bed?”
“You’d have to be a fool to want to bed Selyse Florent,” said Littlefinger. “Doubtless Patchface reminded her of Stannis. And the best lies contain within them nuggets of truth, enough to give a listener pause. As it happens, this fool is utterly devoted to the girl and follows her everywhere. They even look somewhat alike. Shireen has a mottled, halffrozen face as well.”
Pycelle was lost. “But that is from the greyscale that near killed her as a babe, poor thing.”
“I like my tale better,” said Littlefinger, “and so will the smallfolk. Most of them believe that if a woman eats rabbit while pregnant, her child will be born with long floppy ears.”
Cersei smiled the sort of smile she customarily reserved for Jaime. “Lord Petyr, you are a wicked creature.”
“Thank you, Your Grace.”
An inability to wage an effective propaganda war
Ser Kevan cleared his throat. “I would sooner have Petyr Baelish ruling the Eyrie than any of Lady Lysa’s other suitors. Yohn Royce, Lyn Corbray, Horton Redfort... these are dangerous men, each in his own way. And proud. Littlefinger may be clever, but he has neither high birth nor skill at arms. The lords of the Vale will never accept such as their liege.” He looked to his brother. When Lord Tywin nodded, he continued. “And there is this - Lord Petyr continues to demonstrate his loyalty. Only yesterday he brought us word of a Tyrell plot to spirit Sansa Stark off to Highgarden for a visit and there marry her to Lord Mace’s eldest son, Willas.”
“Littlefinger brought you word?” Tyrion leaned against the table. “Not our master of whisperers? How interesting.”
Cersei looked at their uncle in disbelief. “Sansa is my hostage. She goes nowhere without my leave.”
“Leave you must perforce grant, should Lord Tyrell ask,” their father pointed out. “To refuse him would be tantamount to declaring that we did not trust him. He would take offense.”
“Let him. What do we care?”
Bloody fool, thought Tyrion. “Sweet sister,” he explained patiently, “offend Tyrell and you offend Redwyne, Tarly, Rowan, and Hightower as well, and perhaps start them wondering whether Robb Stark might not be more accommodating of their desires.”
“I will not have the rose and the direwolf in bed together,” declared Lord Tywin. “We must forestall him.”
Complete disregard for the delicacy of her tenuous diplomatic position.