Scientist: U.S. has too many nuclear weapons

As Laura Grego spoke to a group of Bates College students about the many dangers of nuclear arms, news was coming across the wires.

"North Korea has followed through on its threat to advance its nuclear weapons program," according to The Associated Press, "while a research institute pointed to signs the communist country is preparing to launch bigger rockets."

That will come as no surprise to Grego, a senior scientist in the Union of Concerned Scientists Global Security Program. As an expert on space security issues, she knows how precarious things have become in the world of nuclear defense.

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