Dealing with the linkage and compatibility of international and national environmental law, this work analyzes how and to what extent international environmental law, primarily through various types of treaty obligations, limits the discretion of states in their national implementation. The text goes on to examine a large number of international instruments with regard to their adequacy for guiding states towards common environmental objectives. Throughout, the author argues for a relaxation of the distinction between international and national environmental law, eg in the decision-making of domestic institutions. The suggestion is made that certain legal elements should be emphasized in the establishment of international regimes on sustainable development.