Do you know how easy it is to hack such a system?
Not very, actually.
One would have to enslave ever how many computers you could hack in order to do it.
It wouldn't be worth anything to anyone, actually, 'cuz the costs of doing it would be EXORBITANT, and the return wouldn't be worth it.
Virus and trojans are all over the net. You do not have to hack the main vote counting system just spread it around to all of the users computers.
obama would win 2012 with 315 million votes