In recent years, U.S. nuclear weapons policy has been focused on arms reduction to address current security challenges posed by the threats of nuclear terrorism and nuclear proliferation. According to the 2010 Nuclear Posture Review, changes in the international nuclear security environment, including an easing of cold war rivalries and a growth in U.S. conventional military capabilities, enable the United States to address these security challenges at lower nuclear force levels and with reduced reliance on nuclear weapons.