In his April 2009 Prague speech, President Barack Obama ambitiously pledged to "secure all vulnerable nuclear material around the world within four years." The goal is driven by the need to ensure that terrorists never obtain a nuclear weapon or materials usable for a nuclear device, and its urgency cannot be overstated.
Twenty countries are believed to possess bomb-grade nuclear material that is not secure. While fissile material security is usually associated with developing countries, developed countries such as the U.S. must also take additional steps to safeguard their own nuclear materials. What's more, despite a myriad of national laws and international agreements, there is no universal standard for how safe and secure nuclear materials need to be.
Significant progress has been made since the president's Prague speech. In September 2009, Obama chaired a special U.N. Security Council session on nuclear nonproliferation and disarmament, which endorsed a four-year timeframe for securing vulnerable nuclear material.