by Sheila AshThe Chief U.S. negotiator for a treaty on the reduction of nuclear weapons was in town Friday to address the Louisville Committee on Foreign Relations.Assistant Secretary for Arms Control Rose Gottemoeller's speech focused on the New Strategic Arms Reduction Treaty with the Russian Federation. START limits the number of deployed warheads each nation may have to 1,550, down from 2,200. Both countries, though, may still stockpile thousands of inactive warheads.Gottemoeller says the U.S. must keep nuclear weapons out of the hands of terrorists.That is the most significant threat today," she says. "The United States doesnβt worry so much any more about a nuclear attack from the Soviet Union that was the cold war problem that was the cold war threat number one. But nowadays the threat number one is the threat of terrorism and particularly the threat of nuclear weapons in the hands of terrorists.)The New START was signed earlier this year and is before the Senate for ratification. The first treaty expired in 2009.