In Geneva, Mikhail Gorbachev and President Reagan pledged to reduce nuclear warheads by at least 50 percent for the first time.

Asked whether failure to win a binding treaty on reducing nuclear warheads would damage that confidence, he replied: "It will depend on the way we develop our relations across the board.

After ratification of the Start treaty, signers of the treaty would begin to reduce long-range nuclear warheads on missiles and on bombers in three stages over a seven-year period.

Besides, the best way to cope with such remote risks would be to further reduce and control warheads scattered around the Soviet Union.

During the Clinton years, Washington and Moscow announced plans to negotiate a new treaty to reduce total long-range warheads to somewhere between 2,000 and 2,500.

Status: The United States and the Soviet Union have agreed to reduce nuclear warheads on long-range weapons to 6,000 each.

The original Start treaty would have reduced Russian and American warheads to about 7,000 apiece.

These include Mr. Gorbachev's pledge to reduce strategic warheads by an additional 1,000 beyond planned treaty limits to a total of 5,000 warheads.

The treaty commits the United States and Russia to reduce strategic intercontinental nuclear warheads to 3,500 each within seven years.

During the Iowa caucuses, he referred to the Treaty on Intermediate-range Nuclear Forces first as reducing launchers and then as reducing nuclear warheads.