This is the biggest revolt Bush has faced and it comes on the issue that has been the core and heart of his presidency, namely security.

Primary electorates tend to be more extreme electorates and a vote like Iraq, that was popular and centrist at the time, is going to be a lot less popular in the primary.

The expectations game can make a lot of difference, ... But people are looking at what the campaigns say much more skeptically this year.

Until now, Bush's approach has been defensive: We are a nation at war, and we can't afford a change, ... And lately, people seem to agree with him.