For now, Washington is simply feeling its way, trying to balance security and cost while tending to the countless other battles it must fight on the home front. Given the power of even a single rogue nuke, however, this battle is clearly one of the most important. "The consequences of failure would be far worse than Sept. 11," says Alexander Strezov, a Bulgarian scientist who helps investigate trafficking cases. "To be honest, I don't want to think about it." The U.S., unfortunately, doesn't have that luxury.