EMP

An EMP could be launched without a nuclear weapon on any city at any given time its just about who is capable of acquiring or making one. The threat of one from a nuclear warhead is the main idea and many country's have access to them, but many other country's have the ability to just produce an small EMP that could cripple most areas on the Eastern Sea Board. It would also take a lot of time for the new parts to fix all of the damage done by the EMP its still unknown if an imitate attack is approaching.