The recent case of Illinois v. Milwaukee, 2 ELR 20201 (U.S. 1972), clears the way for the federal district courts to apply federal common-law principles in the resolution of interstate environmental controversies. This new development, which was first discussed in ELR comments on Texas v. Pankey, 1 ELR 20089 (10th Cir. 1971), and Ohio v. Wyandotte, 1 ELR 20124 (U.S. 1971), carves out an important exception to the Erie doctrine and definitely enlarges the role the federal courts can play in environmental protection. See Comments at 1 ELR 10018 (February 1971) and 10038 (March 1971). If the federal district courts willingly implement their new mandate, they will develop a body of law that will fill the gaps presently existing in the patchwork of federal and state environmental protection statutes, stimulate more effective regulatory efforts, focus congressional attention on neglected interstate environmental problems, supplant state law and state courts where they have inadequately dealt with interstate problems, and grant the states, their individual citizens and the federal government a new source of power to cope with environmental degradation.

The advisability of such a development in federal law was discussed favorably in the earlier ELR comments. The pros and cons will not be further discussed here.¹ Rather, because the Supreme Court has already indicated that the district courts should apply federal common law in appropriate cases, this Comment will review the cases that involve the new theory and will discuss the possible scope of the new cause of action.