what happens when President Logan screws up royally? When he ties the hands of CTU and the FBI? When he plays right into the hands of the terrorists?
Mike Novak has already proven that he will subvert a president if he thinks him incapable of his duties and that was with a trusted friend. How long before he steps in and gets mealy-mouth kicked out and supplanted by SecDef Heller?
Obviously, there are some succession questions there but Heller is on the president's cabinet and while the SecState or Speaker of the House would be a more natural choice, the overiding factor would be the security of the nation and for that Heller is the obvious choice. Of course, the most important factor here is that the fans love Heller's red-faced, give 'em hell politics and we don't even know anybody else so...duh.
I say this won't be till next week, after the poo has really hit the fan. by then, Jack will be one step behind Marwan and one step of the FBI who will be looking for him on orders from Mealy. Heller will be able to come in and help just in time to help Jack capture the missing warhead.