THE Fifth Amendment of the Bill of Rights - part of which guarantees that private property shall not be taken for public use without just compensation - and the national goal of protecting the environment are on a collision course in Congress and the federal courts. The fallout could include accelerated destruction of wetlands, endangered species and other natural resources - and a field day for lawyers challenging environmental regulations.In Congress, Sen. Steve Symms (R) of Idaho has proposed legislation to block the implementation of any federal regulation until the attorney general has reviewed it for potential impacts on private-property rights. In June, Senator Symms successfully attached his bill as a rider to Senate transportation legislation. House and Senate conferees on the transportation bill are now debating whether to adopt the amendment. In the federal courts, private property advocates are pursuing litigation designed to expand the Fifth Amendment as a bar to government environmental regulation. The federal claims court, which hears suits for damages against the government, has accepted the argument in several cases that wetland regulations under the federal Clean Water Act can produce an unconstitutional "taking." On Nov. 19, the Supreme Court agreed to review a decision by the South Carolina Supreme Court that had upheld against a tak ings challenge a state law requiring that oceanfront development be set back from the shore. At stake is the ability of federal and state governments to slow the continuing destruction of wetlands at the rate of 300,000 acres per year, protect critical habitat for endangered species, and prevent ecologically destructive and economically wasteful development in floodplains and along ocean shore. Interest in the "takings" issue grows out of a decision by the Justice Department under the Reagan administration to use the Fifth Amendment to control government regulation. As recounted in a recent book by former US Solicitor General Charles Fried, the department developed the goal of using "the takings clause of the Fifth Amendment as a severe brake upon federal and state regulation of business and property." The purpose of the Symms bill is to incorporate into the federal statutes an executive order issued by President Reagan in 1988 that grew from this effort. The order requires federal agencies, before taking regulatory action, to identify the "takings implications" of the action and minimize interference with private-property rights. The order defines a "taking" to include any "regulations imposed on private property that substantially affect its value or use," even if "the action results in less than a c omplete deprivation of all use or value." IT has been established that the protection of the Fifth Amendment is not limited to a situation where government actually seizes private land for a public purpose, such as a highway or landfill. In the words of Justice Oliver Wendell Holmes, "the general rule at least is that, while property may be regulated to some extent, if regulation goes too far it will be recognized as a taking." To date, however, the scope of permissible government regulation under the takings clause has been quite expansive. The Supreme Court has recognized that a mere reduction in property values is not sufficient to support a takings claim. A property owner's desire to make the most profitable use of his or her land has never been recognized as a constitutional right. These precedents are based in part on a recognition that government activities - from road construction to taxation policy to zoning regulation s - affect private-property values, both upward and downward. It is not practical to seek to compensate individuals for these constant fluctuations in value. The Supreme Court has also recognized that a landowner is not entitled to compensation if the regulatory purpose is to prevent harm to other citizens. The court has recognized the government's right to destroy a grove of trees on private property to prevent the spread of disease, or to block underground coal mining that would interfere with other land uses. Destruction of wetlands inflicts the same kind of harm to the public. Wetlands serve important public functions, including flood control, elimination of water pollution, and as wildlife habitat. Destroying wetlands injures the public as a whole as well as the particular citizens affected by increased flooding or pollution problems. The takings dispute ultimately transcends narrow questions of law. How our society resolves the issue will tell a great deal about whether we understand our common dependence on healthy, functioning ecosystems.