NO one is publicly arguing against the protection of wetlands. These marshes, swamps, and bogs are widely recognized as critical to water purity, flood control, and the nurturing of fish and waterfowl.But consensus dissolves over the question of what's wet enough to get the official tag of "wetland." Under the Bush administration's new guidelines, which came out of the Council on Competitiveness chaired by Vice President Quayle, the wetness line is drawn much nearer the liking of business and agriculture. Some experts say as many as half the 100 million remaining acres of wetlands could lose protection if the new standards are adopted. Farmers and builders counter that government regulation ought to be trimmed back to its original purpose - conservation of land that's truly "wet," not occasionally damp. But wetlands that aren't under water for the 15 consecutive days demanded by the revised standards are not necessarily less deserving of preservation; they can still be essential to flood control or wildlife feeding. The administration's proposal would greatly reduce the amount of such land entitled to protection, and many states would probably follow the federal lead. But legislation now before Congress would go further, eliminating the Environmental Protection Agency's final say over the use of much protected land. It might be better to live with the new administrative rules, some argue, than risk a legislative gutting of wetlands regulation. Even better would be retention of the broad protection provided by current rules, with administrative tightening to assure the regulations are fairly and consistently applied. The loss of wetlands has to be stopped. Are the regulations in effect since 1989 as burdensome as critics assert? Ninety-five percent of land-use permits applied for under current regulations are approved, and the law gives broad exemption to farmland. Government intervention in the use of private property is never welcome, but it's well established in law. Wetlands are a public good that demands protection, as President Bush acknowledged when he promised "no net loss."