Can the Feds Shut Down Cell Phone Service?

In the aftermath of yesterday’s tragic bombings at the finish line of the Boston Marathon, there were reports that cell phone service in the region had been cut off to avoid the detonation of another bomb via cell phone.

Ultimately, those reports were unfounded. Mobile networks were simply jammed as people frantically tried to get in touch with friends and loved ones.

But in an age when our smartphones are a constant companion, what is the protocol for shutting down wireless networks in an emergency? Is it allowed, and would it even help?