(FORTUNE Magazine) – ''If talk about 'free trade' puts you to sleep, you'd better wake up fast!'' So begins a newspaper ad campaign backed by a coalition of environmental, labor, and consumer groups out to sabotage the Uruguay Round of GATT negotiations. The ads, which cost $74,000, ran in the New York Times on April 20 and the Washington Post on April 22. That was the day President Bush and U.S. Trade Representative Carla Hills met with European Community President Jacques Delors in what turned out to be another vain effort to persuade Europe to cut agricultural subsidies. The ads argue that GATT's attempt to harmonize global trade regulations would override U.S. laws that protect health, jobs, and the environment. One example, provided by Lori Wallach, an attorney for Public Interest, the consumer group founded by Ralph Nader: A GATT panel ruled last year that American laws banning the import of tuna not ''dolphin-safe'' violated international free-trade agreements. The decision suggested that a country could refuse imported tuna only if it was spoiled, say, and a health threat. Says Wallach: ''It basically means if the tuna doesn't give you botulism, it doesn't matter if you drown Flipper on the way.'' Former Secretary of Labor William Brock, a free-trade supporter, calls the ads ''deceptive and irrational.'' He cites a recent Organization for Economic Cooperation and Development study, which predicts that a new GATT agreement would result in a $195 billion increase in world income by the end of the decade. Says he: ''It would be really dumb to regress at this point.'' Maybe. But 138 Congressmen are sponsoring a resolution that would vote down any GATT agreement that rides roughshod over U.S. laws. - R.T.