Paullus Fabius wrote "Well, it wasn´t exactly against the mos maiorum. These were self-confessed traitors and were a security risk. A trial would have taken ages... and they would have had to be confined somewhere -this is what Caesar advocated- to await it... that would have been dangerous and even more unconstitutional" I think this explanation would fit better at Cicero' thread. As a chief officer of the goverment at the time he may have his reasons (whether valid or not), but Cato, as just another senator debating the matter over, is a completely different case (imho). His un-flexibility, his principles, his opposition to changes are only way too well known, and that is why this sudden advocation of such dramatically rules-breaking precedent is just... doesn't fit with the whole picture of Cato! There were too many instances in which, when it came over his high prised principles, he wouldn't bent even for the good of the state, so why this time? And why such sharp turn of 180%? (I'm afraid Heraclia just answered that "there's no way to rationalize that Cato could occasionally go right off the rails in terms of the mos maoirum...")