Senator Jay Rockefeller laid it out today on the Sunday morning circuit (via AFP):

Half of Russia's nuclear materials that can be used by terrorists plotting new attacks against the United States remain unaccounted for, a US senator with access to classified intelligence information charged.

John Rockefeller, vice chairman of the Senate intelligence committee, said the situation with Russian loose radioactive materials and other possible components of nuclear weapons made him wonder whether Russia was a greater proliferation threat than North Korea, which has publicly claimed to have a nuclear weapons arsenal.

Members of the committee received last week a detailed briefing from Central Intelligence Agency officials on security threats faced by the United States.

"In the sense that half of the nuclear materials, pieces and parts of it, are unaccounted for by the Russians -- and a lot of them, these places are in rural areas -- I think you can ... have a real debate as to which is more threatening to the world right now," said the Democratic senator, appearing on the "Fox News Sunday" television program.

I'm glad President Bush looked into Vladimir Putin's eyes and saw good, but "loose nukes" in the former Soviet Union are clearly the greatest threat to the American people. Iraq, by comparision, and perhaps even Iran and North Korea, pale in comparison with the hundreds of unaccounted for nuclear weapons. It's good to know that the President is more concerned about rattling the saber at Syria than he is about unwatched Russian nukes, though.