Dual sovereignty is a central characteristic of the U.S. federal system and involves powers exercisable by Congress and state legislatures. The latter may use these concurrent powers and other reserved powers to cooperate with each other or to create regional or national problems.
The erection of trade barriers by states between 1781 and 1788, under the Articles of Confederation and Perpetual Union, was a primary reason for the convening of the 1787 Constitutional Convention in Philadelphia to revise the articles. Based on this historical fact, one would anticipate that interstate relations would be featured prominently in the literature on the federal system. A review of the literature is disappointing, as such relations generally have been neglected with the principal exception of law review articles examining certain legal aspects of the relations. Literature focusing on the politics of interstate relations is sparse and typically old.
Improved communications and transportation systems in the post- Civil War period promoted mobility of citizens and development of multistate and, more recently, multinational corporations. The lack of uniform state statutes on a wide variety of subjects creates serious problems for citizens traveling to other states and for corporations. Although organized efforts have been made since 1892 to harmonize diverse state laws, nonuniformity characterizes statutes on numerous subjects.
The failure or inability of states to solve several important transboundary problems has resulted in increasing congressional preemption of their regulatory authority since 1965. Preemption during the past three decades has produced significant changes in the nature of the federal system in general and relations between states in particular. Congress currently is debating several bills, including product liability ones, that upon enactment would remove more regulatory powers from states. Additional preemption clearly will impact negatively the ability of states to use their respective discretionary powers to solve problems on a cooperative basis with sister states and the balance of powers between Congress and the states.