I’ll nutshell this one…
Basically Robertson says God had forsaken us for our secular, gay loving ways so we deserved 9/11.  So, we need Rudy, (the secularist, gay loving, quasi-Republican in charge of the secular, gay loving city that God had forsaken), not God, to protect us.  
Makes perfect sense.
Talking Points Memo | Rudy’s New Pal

and just for more clarity on this:
Election Central | Talking Points Memo | Flashback: Rudy Attacked Ron Paul For Blaming America For 9/11