Beginning with the Articles of Confederation, states used Compacts to settle boundary disputes.  In 1918, Oregon and Washington enacted the first Compact solely devoted to joint supervision of an interstate resource (fishing on the Columbia River). Three years later, New York and New Jersey enacted the first Compact to create an interstate commission (now known as the Port Authority of New York and New Jersey).

Today, more than 200 interstate Compacts directly regulate or guide policy for a range of matters as diverse as the use and allocation of water, land, and natural resources. There are Compacts for environmental protection, transportation systems, regional economic development, professional licensing, education, crime control and corrections, and child welfare. The U.S. Supreme Court has a history of encouraging states to resolve disputes through Compacts rather than litigation.  E.g., Vermont v. New York, 417 U.S. 270, 277–78 (1974). A seminal law review article notes, “The combined legislative powers of Congress and of the states permit a wide range of permutations and combinations of power necessary for governmental action.”  Felix Frankfurter & James M. Landis, The Compact Clause of the Constitution—A Study in Interstate Adjustments, 34 Yale L.J. 685, 688 (1925).

The ICAOS, like the 1937 Parole and Probation Compact, is integral to the longstanding and increasingly prevalent use of interstate Compacts. Similar to its predecessor, the ICAOS addresses multilateral issues that extend beyond state boundaries.