He could win all the blue state republican primaries (Rudy easily wins NY,MA,NJ,NH,VT,CA,OR,WA,ME,CT,PA,MD,DC,HI) and get enough of the red state delegates to put together a win.
There are too many moderates/liberals going to run in 2008 to consolidate that small GOP voting bloc behind one candidate. In short, they will split the vote and lead the way for a single conservative candidate to get the nomination.