As conventionally understood, social movements, law reform, and society interact in a
unidirectional fashion. Social movements seek to secure law reform; in turn, changes in
the law bring about changes in society. While this conventional understanding may be
helpful for some purposes, it is an incomplete empirical account that can lead
reformers mistakenly to think that legal change is sufficient in order to achieve changed
social conditions. In fact, social movements, law, and society interact with each other
in much more complex, dynamic ways. Through an examination of the environmental
movement in the United States, I show how a successful social movement not only
uses law reform to change society, but how it also depends on changes in society to
sustain its law reform efforts. For the environmental movement, the public''s consistent
acceptance of environmental values has helped sustain the laws brought about by the
movement, even in the face of significant resistance. Even though social movements use
law reform to affect society, society in turn affects the success of law reform. As a
result, sustainable social movements will combine efforts at legal change with efforts to
change underlying social values.