I know it's Hollywood at it's best, but I'm reminded of the movie "Live Free or Die Harders". Is it possible that events as those depicted in that movie could happen? I say "YES". It's already a known fact that there are vunerablilities in some of our utilities grids. Water, eletricity, banking...most of these entities are controlled largely by computers or are intriquetly linked to the Internet. When you really stop and think about it, I can understand why in a 21st Century world our government would be considering giving emergency powers to the President (or someone within the White House) the ability to take charge of cyber activites in a major crisis.
We're in a post-9/11 world and cyber attacks have been occuring at various levels of private and government sectors for a while. They just aren't readily reported, but it happens. How successful this nation has been at stopping such attacks is up for debate, but that doesn't mean that we shouldn't give strong consideration for planning against such cyber attacks including giving emergency powers to the President.
Again, we view such powers as treading on our privacy, and I can completely understand the nervousness in that regard as it applies to day-to-day life or the government's ability to swoop in and do whatever it wants. But we have to look at this issue from 21st Century threats and recognize it's not about the day-to-day access, but "in the event of a national emergency where the security of our public/private utility/cyber-grids are threatened." I wouldn't necessarily give up sweeping powers, but I'd be okay with a government/private sector partnership in this regard.