On a related note, I have a hard time believing a former costumed hero can seriously kill half of New York and just shrug it off. Even Rorschach thought it was fucked up -- and that should tell Ozymandias something.

The idea was, the Cold War never ended and with the Doomsday Clock at less than a minute to 12, Ozymandias justified (to himself) that half a city dead was much more palatable than the loss of an entire world. And his method of execution, if you will, was one to unite all countries towards a common goal -- protection against a common threat so mind-blowingly fucked up that they wouldn't dare do anything but cooperate.

Of course, with Rorschach's journal (possibly) being published after the final panel, Ozy's plans may have ultimately come to naught.