By Fissile Materials Working Group | Jun 8, 2010
If the car bomb in Times Square contained just one of the tens of thousands of radioactive sources that exist in the U.S. and it had successfully detonated, this American landmark would be uninhabitable for months or years to come. And, if the attack were with an improvised nuclear device instead, a large portion of Manhattan would have been destroyed. We were lucky in many ways that day, but these are real threats posed by ever-bolder terrorists, and our luck might not last forever.