Environmental law has been defined as the law of planetary housekeeping. It is concerned with protecting the planet and its people from activities that upset the earth and its life-sustaining capabilities, and it is aimed at controlling or regulating human activity toward that end.

Until the 1960s, most environmental legal issues in the United States involved efforts to protect and conserve natural resources, such as forests and water. Public debate focused on who had the right to develop and manage those resources. In the succeeding decades, lawyers, legislators and environmental activists increasingly turned their attention to the growing and pervasive problem of pollution. In both instances, environmental law—a term not coined until 1969—evolved mostly from a grassroots movement that forced Congress to pass sweeping legislation, much of which contained provisions for citizen suits. As a result, the courts were thrust into a new era of...