WASHINGTON, D.C.: Arm-twisting was in full-swing in the Senate Thursday as the long-debated global chemical weapons treaty neared a final floor vote. The White House won crucial support from a number of wavering Republicans, including Senate Majority Leader Trent Lott, after President Clinton offered last-minute assurances that the U.S. would withdraw from the treaty if it ever becomes necessary to protect America against the spread of chemical weapons. Despite strong opposition from many of his conservative colleagues, Lott hailed the offer as an "ironclad commitment" from the White House and said the U.S. will be "marginally better off with it than without it." With some 17 Republicans pinning their decisions on whichever way Lott voted, his move could be enough to muster the two-thirds majority that is required for ratification. The treaty would ban the use, development, production or stockpiling of all chemical warfare agents and require the destruction of existing stockpiles over the next decade. Many Republicans fear signing such a pact would leave America weak as countries around the world secretly build chemical weapons. But failure to pass the treaty would be seen as a serious setback for U.S. foreign policy, notes TIME's Doug Waller. "The U.S. would join pariah states like Iraq, Iran and North Korea that have refused to ratify." Signed by 164 nations thus far, and ratified by 75, the pact will take effect April 29 regardless of whether it is ratified by the U.S.