We are always prepared to fight the previous war. If the US ever goes against any country with a significant tech base, we will not be prepared. To be fair, though, the US is prepared to fight without the internet, it will just be an inconvenience. The Future Warrior program was supposed to rely heavily on digital information systems, but it is now mostly canceled. The military is still using the same methods they did in the 80's and 90's (dedicated sat-links and voice channels)before the net got so integrated into daily life. The real problem would be on the civilian front where massive cyber-attacks could blackout good-sized chunks of infrastructure. But, the civilian sector already has to deal with that from botnets attacking a company's online presence to coerce money out of them. Therefore, there is already defenses being designed to combat this. Maybe the military is just going to keep things totally separated from the net to make it hard for any attack to even start to cause problems.