An EMP attack would mean he can stay as a dictator for the rest of his life. He will have only 10% of the population to deal with. Not so bad for O.
For Obama to want to be “in charge” of a wasteland with absolute chaos among those that didn’t die in the first 6-12 months (would depend on what time of year it occurred), is unthinkable. There’d be no communication, and thus the inability to issue orders to anyone that would extend much past pony-express routes (or with any greater speed). Obama needs to be in control of a large population to meet his ego-maniacal needs. Can you imagine what he would do if he couldn’t be in front of a TV camera to put his nose in the air, and do his theatrics, and threaten people, and show how powerful he is to the masses? He’d melt down without that, having now experienced it!