WASHINGTON: Backed by a distinguished array of supporters, President Clinton may finally have landed his chemical weapons ban treaty. Lawmakers, diplomats, arms experts and military leaders all gathered on the South Lawn to help promote U.S. ratification of the 161-nation Chemical Weapons Convention before the April 29 deadline. Former Secretary of State James Baker warned that rejecting the treaty "will be sending a clear signal of retreat from international leadership. This is a message we should never send." Colin Powell endorsed it Friday. Dick Lugar, former Kansas Senator Nancy Kassebaum Baker, former Bush adviser Brent Scowcroft and President Bush himself all supported passage as well. So who stands in the treaty's way? "A small but vocal minority of harder-edge, right-wing Republicans," says TIME's Mark Thompson, "making the traditional argument against international treaties, that only the honest will comply. The U.S. throwing open its doors, the inspectors coming in and out, our secrets possibly falling into the wrong hands -- these things are distasteful from what is very much an isolationist posture." But Thompson thinks the resistance was softened by Madeleine Albright's full-bore wooing of a certain North Carolina Senator. "Helms' buckling last week pretty much sounded the death knell for the opposition," he said. "The treaty will take effect with or without us. It has holes and problems, but it represents a standard, so that when you have violators, there is something on which to take them to task." And the effectiveness of that standard depends rather heavily on the world's dominant military power. "It's important for the U.S. to take a lead," says Thompson. "If we don't, that just makes it easier for a small, rogue nation to opt out as well, just by leaning on the same reasons we gave."