Reasons given by the aides were loyalty to the campaign manager McCain replaced last week.

First, we're at least six months off from the primaries and seven and eight months off from the majority of them. That's bad news for McCain. It seems that the longer he's in the spotlight, the greater people's dislike for him. His nation-wide average polling high once all the major candidates had announced was around 26-27% back in February. Since then, he's been on a downward slide. He's now at 12-14%. At that rate he'll hit bottom just in time for the new year. Fortunately we probably won't have to wait that long for him to drop out of the race.

Second, he really took some hits during the immigration bill debate. Some people disliked him for his support of the bill. Others began to realize what a jerk he is when word of his attrocious treatment of his fellow senators came to light. But the important thing both groups had in common is that their opposition to the immigration bill and its proponents crossed party lines and, more importantly for McCain, crossed intra-party ideologies. This isn't a question of the "base" abandoning him. People of every ideology hated that bill including social cons and paleocons and neocons and even some fiscal cons (not to mention the democrats who opposed it, too).

Third, this is not unexpected. McCain liked the "maverick" label, but found that it is pretty difficult to be a party maverick and still be the "base's candidate" (setting aside the difficulty of describing just which group constitutes the base).

Finally, it is unlikely that "failure to play to the base" is the sole reason for McCain's demise. Giuliani has taken positions which depart significantly from that of the party as a whole. That may have some people upset, but he hasn't been punished for it in the polls yet. (According to Rasmussens latest, Giuliani is nationally at 23%.)