President Barack Obama delivers remarks to the Nunn-Lugar Cooperative Threat Reduction symposium held at the National Defense University at Fort McNair in Washington, D.C., Dec. 3, 2012. Joing the President on stage are, from left: Defense Secretary Leon Panetta; former Sen. Sam Nunn, D-Ga.; and Sen. Richard Lugar, R- Ind.(Official White House Photo by Sonya N. Hebert) On Monday, President Obama traveled to the National Defense University to mark the 20th anniversary of what he called "one of the country’s smartest and most successful national security programs" -- the Nunn-Lugar Cooperative Threat Reduction Program for the destruction of weapons of mass destruction in the former Soviet Union. And after celebrating some of the accomplishments of that program, the President discussed the need to continue that nonproliferation work in the decades ahead. "We simply cannot allow the 21st century to be darkened by the worst weapons of the 20th century," he said. "And that’s why, over the past four years, we’ve continued to make critical investments in our threat reduction programs -— not just at DOD, but at Energy and at State. In fact, we’ve been increasing funding, and sustaining it. And even as we make some very tough fiscal choices, we’re going to keep investing in these programs —- because our national security depends on it." President Obama also delivered a specific message to Syrian President Bashar al-Assad. "On Syria, let me just say this. We will continue to support the legitimate aspirations of the Syrian people -— engaging with the opposition, providing with -- providing them with the humanitarian aid, and working for a transition to a Syria that’s free of the Assad regime," the President said. "And today, I want to make it absolutely clear to Assad and those under his command: The world is watching. The use of chemical weapons is and would be totally unacceptable. And if you make the tragic mistake of using these weapons, there where be consequences, and you will be held accountable." President Obama concluded his remarks by telling the story of a trip he took to the Ukraine with Senator Richard Lugar when both men were in the Senate. "We went to a facility, an old factory," he said. "We walked down these long, dark corridors. Finally, we came across some women, sitting at a worktable. On it were piles of old artillery shells. And the women were sitting there, taking them apart. By hand. Slowly. Carefully. One by one." "It took decades -— and extraordinary sums of money -- to build those arsenals," President Obama told the audience today. "It’s going to take decades -- and continued investments --to dismantle them."