Senator Ted Kennedy (D-MA) offered an amendment to the National Defense Authorization Act Amendment to block the start of site preparation at the SIS (Special Isotope Separation) plant in Idaho for fiscal year 1990. The House had already adopted similar language in committee.

The $1.2 billion facility is intended to convert spent fuel from nuclear reactors into material that could be used to manufacture nuclear warheads for missiles and bombs. Environmentalists have opposed the SIS facility for several reasons. All the evidence points to a decline in the need for plutonium: the Department of Energy closed down a plutonium production facility in Hanford, Washington recently and is presently obtaining most of its plutonium by recycling the material from retired warheads. In a tight budget, the $1.2 billion appropriated for this project diverts funds desperately needed for environmental clean-up and safety improvements at DOE sites.

On July 31, 1989, Senator John Warner (R-VA) offered a motion to table the Kennedy amendment. Warner's motion was accepted with a vote of 50-49. No is the pro-environment vote.