The rise of Ron Paul makes that clear. Ron Paul is super hard right, except he is anti-war. And he has become the outsider's candidate.
The Republicans are between a rock and a hard place on Iraq and Bush. If they support either they loose support among the majority of the Republicans, because the general body of Republicans is anti-war and want a change from Bush at this point. But if they go against the war or Bush they anger a small party core that is pro-war at any cost. This group is small, but made up of party activists, money backers and other key party members. And it isn't something they can waffle or avoid, they have to be either pro-war or anti-war, either pro-Bush or anti-Bush.
This is exactly why no candidate is really popular on the Republican side. Nobody can satisfy both the party core and general body at the same time right now. Recent polls suggest that despite the number of candidates and debates, "none of the above" is still the most popular position among Republicans.
McCain has basically seen everything go wrong. Because his popularity was grounded in not following the party line, his sudden conversion to party loyalist has angered his fans. And the party loyalists remember his previous behavior and expect he will abandon the party line if elected.
Be pro-war, backing Bush and supporting conservative religion are all on this track. And all have crippled McCain but it is far too late for him to back track. At this point all he can do is keep his head low and hope the others crash.
Jay