The next Pearl Harbor will not announce itself with a searing flash of nuclear light or with the plaintive wails of those dying of Ebola or its genetically engineered twin. You will hear a sharp crack in the distance. By the time you mistakenly identify this sound as an innocent clap of thunder, the civilized world will have become unhinged. Fluorescent lights and television sets will glow eerily bright, despite being turned off. The aroma of ozone mixed with smoldering plastic will seep from outlet covers as electric wires arc and telephone lines melt. Your Palm Pilot and MP3 player will feel warm to the touch, their batteries overloaded. Your computer, and every bit of data on it, will be toast. And then you will notice that the world sounds different too. The background music of civilization, the whirl of internal-combustion engines, will have stopped. Save a few diesels, engines will never start again.
Given that the US military has a highly advanced E-bomb programme, they may also prove useful for sending rogue states (i.e., anybody whose politics we have problems with) back into the 19th century. Or, when the time comes, making the rigth to use electronic devices dependent on signing a treaty mandating universal copy-protection and/or surveillance, and reserving the right to EMP non-signatories (who must be dens of piracy and terrorism).