Secure or seclude : U.S. nuclear policy and nuclear states, a comparison of India and Pakistan

The U.S. has implemented a two-track nuclear policy since the Cold War. The first track is non-proliferation and the second track involves securing all nuclear materials. The two-track nuclear policy has been effective, but at times non-proliferation efforts are contradicted by the US supporting nuclear programs by securing nuclear materials. The current greatest threat to nuclear security is the acquisition of nuclear materials by an extremist or terrorist organization. Can the US combat the current growing threat of loose nukes with the two-track policy?