The Scabbard Of the Morning, on Jan 6 2008, 00.28, said:
Her freeing Jaime was understandable to me because she's a grieving mother. But tactically it is not defensible as a positive or even neutral move. It was a terrible move. It lost Robb his biggest bargaining chip, and even more importantly it killed the morale of Robb's troops and sowed dissension among his bannermen, things which a king at war simply cannot afford.
No, the terrible move was Robb marrying Jeyne Westerling - it killed the morale, sowed dissension and made Robb's strategical situation very doubtful, as well as propelled the Freys into Bolton's and Tywin's arms. _And_ he did it quite by himself. And none of his other advisers, who some people consider superior to Cat by the virtue of their maleness alone, managed to prevent that disaster!
Anyway, it made sense to try to get Sansa back ASAP once they got news that Rickon and Bran were "dead". She was now Robb's only heir and as such was worth 3 of Jaimes. Or do you forget how the Lannisters intended to exploit that fact? So, yes, Catelyn may have been a grieving mother, but she also was far more astute politically than any of Robb's loyal lords except for possibly the Blackfish. But she didn't have any direct power, so she had to arrange the exchange in such a half-cocked manner.
And the window of opportunity was closing - Catelyn understood Cersei's character enough to foresee that Sansa was unlikely to survive fall of KL to Stannis. Whereas, if Lannisters managed to win at KL against all expectations, they would have hung on to Sansa at all costs.
In fact, it only highlights Robb's other mistake - he moved out of communication range and in any case was far too occupied with the war to tend to his realm politically. Yet he appointed nobody to do it for him either and therefore the Starks couldn't quickly react to political changes, make diplomatic overtures, seize chances that presented themselves, etc.
And if Jon was with Robb, a lot of things might have happened differently. Jon would have probably advised against sending Theon to meet with Balon.
Who is to say that Robb would have listened to Jon? Jon never liked Theon, but Robb and Theon were bossom friends nevertheless. Nor do I think that Robb could have afforded to give Jon the status some here feel she should have had. Robb depended on the River lords for large part of his support and he was a boy striving to earn the respect of men. As such, making another boy and his bastard half-brother whose very existence offended sensibilities of his allies, his closest adviser, could only damage his own position, IMHO.