Newsweek magazine has obtained commercial satellite photographs demonstrating that Pakistan is "greatly expanding plutonium production for its nuclear-weapons program." Other nuclear powers have learned that deterrence requires only a limited arsenal of weapons. Proliferation creates the possibility of "loose nukes" getting into the wrong hands. Former Senator Sam Nunn, who co-chairs the Nuclear Threat Initiative, calls Pakistan's buildup "extremely dangerous." That's according to Newsweek's article on "Pakistan's Nuclear Surge," by senior editor Andrew Bast.