THE effort to protect America's wetlands has turned into a major confrontation involving federal and state agencies, the White House, and environmental groups around the country.Critics say the Bush administration is not only trying to weaken wetlands protections, but suppressing analysis by government scientists showing that regulatory revisions sought by the White House would leave as much as half of all the nation's wetlands vulnerable to development. As a candidate in 1988, Mr. Bush promised "no net loss" of wetlands, which are crucial to maintaining water quality, wildlife habitat, and flood control as well as providing millions of acres of recreational area and much of the country's commercial fisheries. A federal government manual issued in 1989 moved to stem the loss of wetlands (estimated at 500,000 acres a year) through regulatory enforcement. But under pressure from the oil industry, developers, and farmers, a White House team that included Vice President Dan Quayle revised those regulations - essentially by redefining wetlands. Citing undue political pressure to favor property owners at the expense of environmental protection, several scientists quit the White House team. The proposed changes brought an outcry from environmentalists and state natural resource agencies, some of which are now threatening to ignore Washington and issue their own regulations. The federal agencies involved - the Environmental Protection Agency (EPA), the Fish and Wildlife Service, the Agriculture Department, and the US Army Corps of Engineers - dispatched teams to 450 wetland sites to study the impact of the administration proposal. According to those who have seen the resulting data and analyses, the government scientists came to the same general conclusion as the biologists and hydrologists working for environmental groups and state agencies. "The language used by the federal agency people is at least as harsh as the language that environmental groups are using," said one source who has seen the reports. "In many cases, it is even harsher. They corroborate essentially everything outsiders have been saying." The results of those studies were supposed to have been made public last week, but had not been released at press time. In congressional testimony last week, Jon Kusler of the Association of State Wetland Managers said the scientists making up his organization "are deeply disturbed by a direction in national wetland policy-setting which ignores much of what has been learned about wetland science in the last three decades." "Field tests by the states suggested a 40 to 70 percent reduction in wetland acreage under federal jurisdiction when compared with the 1989 manual," Dr. Kusler said. "Areas excluded include many infrequently flooded areas serving a broad range of habitat, flood storage and conveyance, pollution and sediment control, and other functions and values important to achievement of Clean Water Act goals." In Wisconsin, state Natural Resources Secretary C. D. Besadny says he is "extremely concerned" that revisions proposed by the White House "would remove from 60 to 80 percent (3.2 million to 4.2 million acres) of Wisconsin's remaining wetlands from federal protection" - including much of the wetlands near Lake Michigan. In Florida, "the new definition would leave a huge portion of the Everglades and other areas in the state ineligible for protection," warns Ed Proffitt, state director of the Center for Marine Conservation. This could total "hundreds of thousands of acres in Florida," he adds. "The losses in Connecticut would be 56 percent, Massachusetts 41 percent, Maine at least 60 percent, and Rhode Island at least 48 percent," Joseph Larson, director of the Environmental Institute at the University of Massachusetts, told the congressional panel last week. "In my experience in the environmental field, I have encountered few issues on which the scientific community has such a high degree of consensus," says Environmental Defense Fund lawyer Timothy Searchinger. In announcing the new White House wetlands policy in August, EPA administrator William Reilly acknowledged the "head-on collision between natural systems and their protection on the one hand, and property owners' expectations about their ability to develop their land on the other." The goal remains "no net loss," said Mr. Reilly, who pointed out that the administration had budgeted 48 percent more this fiscal year for wetland acquisition, restoration, and research. But the administration also seeks a more streamlined rules process, Reilly said, and greater predictability for landowners. The period for public comment on the proposals has been extended to mid-December because of the controversy. In Congress, there are several legislative proposals regarding wetlands. One would, in essence, amend the Clean Water Act in line with the recent White House proposals. The bill had about 170 sponsors in the House, but at least five have withdrawn their support as the impact on wetlands became clearer. Another bill would direct the EPA to authorize a study by the National Academy of Sciences of the environmental research and methods of designating wetlands. Still another would give states greater control over wetlands policy.