An EMP strike can easily obliterate America's electrical, telecommunications, transportation, financial, food,and water infrastructures, rendering the United States helpless to coordinate actions and deliver services essential for daily life.
But it would not stop at U.S. borders. Most of Canada would be devastated, too, as its infrastructure is integrated with the U.S. power grid. Much of the world's intellectual brain power (half of it is in the United States) would be lost as well. Earth would most likely recede into the 'new' Dark Ages,"
A detonation over the middle of the continental U.S. has the capability to produce significant damage to critical infrastructures that support the fabric of U.S. society and the ability of the United States and Western nations to project influence and military power.
It doesn't take a "high tech" machine to accomplish this, either.
A determined adversary can achieve an EMP attack capability without having a high level of sophistication. For example, an adversary would not have to have long-range ballistic missiles to conduct an EMP attack against the United States. Such an attack could be launched from a freighter off the U.S. coast using a short- or medium-range missile to loft a nuclear warhead to high altitude.
Terrorists sponsored by a rogue state could attempt to execute such an attack without revealing the identity of the perpetrators. Iran, the world's leading sponsor of international terrorism, has practiced launching a mobile ballistic missile from a vessel in the Caspian Sea.
Iran has also tested high-altitude explosions of the Shahab-III, a test mode consistent with EMP attack, and described the tests as successful. Iranian military writings explicitly discuss a nuclear EMP attack that would gravely harm the United States.
While we do not know the intention of Iran in conducting these activities, we are disturbed by the capability that emerges when we connect the dots.
What we could see is an attack would turn science fiction into reality.
Airplanes would literally fall from the sky, cars and trucks would stop working, and water, sewer, and electrical networks would fail. Food would rot, medical services would collapse, and transportation would become almost nonexistent.
What could happen already has been documented in the 1977 New York City blackout, although on a much smaller scale.
Two lightning strikes caused overloading in the electrical power substations of the Con Edison power company. These lighting strikes, the equivalent of a minuscule fraction of [EMP], caused the Indian Point power plant north of the city to fail, as well as the subsequent failure of the Long Island interconnection. … Failure of the Linden-Goethals 230,000-volt interconnection with New Jersey resulted in the protective devices removing overloaded lines, transformers, and cables from service.
As a result, a power failure spread throughout the New York area. This blackout lasted only one day, yet resulted in widespread looting and the breakdown of the rule of law throughout many New York neighborhoods. The estimated cost of the blackout was approximately $246 million, and nearly 3,000 people were arrested through the 26-hour period.
The blackout in New York City resulted in an immediate breakdown of the social order. The police were outmatched and had no chance of stopping such massive theft, largely having no choice but to stand by watching the looters from a distance.
In North Brooklyn, a community of more than a million residents, only 189 police officers were on duty.
In 2003, a blackout in Ohio, New York, Maryland, Pennsylvania, Michigan and Canada saw massive traffic jams and gridlock when people tried to get home without traffic lights.
Railways, airlines, gas stations, and oil refineries halted operations. Telephone lines were overwhelmed due to the high volume of calls. Overall, the blackout's economic impact was between $7 billion and $10 billion due to food spoilage, lost production, overtime wages.
A true EMP attack could prove even more severe.