The leaders of nearly fifty nations have come to Washington, D.C. to attend the Nuclear Security Summit. This is the largest U.S.-hosted gathering of world leaders since 1945 founding of the United Nations in San Francisco. The goal of the summit is to address the role of nuclear weapons in the world and to discuss how to keep them out of the hands of terrorists. President Obama has made nuclear nonproliferation one of his top priorities and this summit comes right on the heels of the Obama administration’s release of their Nuclear Posture Review and the signing of the replacement START treaty with Russia.

Live on Russia Today, Carnegie's Matthew Rojansky explained the significance of this summit, which gathered world leaders together and excluded those leaders whose countries are believed to be engaged in the illicit development of nuclear weapons, like North Korea and Iran. While last week’s new START treaty was about existing nuclear weapons, Rojansky stated, the Nuclear Security Summit is about the potential to create nuclear weapons and securing the nuclear material found in a number of nations with advanced civilian nuclear capabilities.

Rojansky suggested that the exclusion of Iran had two potential benefits. On the one hand, Iran’s presence could have pulled attention away from nuclear materials and onto nuclear weapons. On the other hand, he pointed out, bringing American, Chinese, Russian, European, and other world leaders together builds a momentum that could be used in the future to engage with Iran as a unified front.

The chief challenge for Obama is to separate the long-term goals, and keep the focus of the summit on nuclear materials security rather than nuclear weapons.