The waterkeeper movement is rooted in the public trust doctrine of English common law. The public trust doctrine says the public owns the commons or shared environments: air, waters, dunes, tidelands, underwater lands, fisheries, shellfish beds, parks and commons, and migratory species. These features of our earth are deemed the ‘gifts of nature's bounty' and therefore are to be reserved for the public. Governments serve as trustees of these gifts, and are obliged to maintain their inherent value for all people, including those not yet born. The public, therefore, is vested with public trust "rights" derived from ‘natural' or God-given law which therefore cannot be extinguished.

    Like muscles, when rights are not exercised, they atrophy. Through the industrial revolution of the 19th and into the 20th century, governments began acting like owners of these resources rather than public trustees. The courts followed suit, interpreting the law to uphold the right of legislators to promote private uses of public resources. Without judicial vigilance, the public trust doctrine fell into disuse except to enforce navigation rights. Governments allowed the de facto expropriation of the ‘gifts of nature's bounty' by private interests, resulting in lost fisheries, lost access to watercourses, dirty air and water, and poor health.

    In the Hudson Valley in 1966, fishermen who were put out of business and citizens who could no longer fish a ‘striper' for dinner went to court to reassert their public right to fisheries and a clean river and won. This case paved the way for citizens to enforce environmental laws when governments fail to do so.

    The political and legislative fall-out over the next decade was impressive. US legislators enacted the Clean Air Act, Clean Water Act, Coastal Zone Management Act, Endangered Species Act, and the Toxic Substance Control Act, among many other environmental laws, all premised on the rights of citizens embodied in the public trust doctrine.