Interstate Compacts are binding on signatory states, meaning once a state legislature adopts a Compact, it binds all agencies, state officials and citizens to the terms of that Compact. Since the very first Compact case, the U.S. Supreme Court has consistently held that a Compact is an enforceable agreement governing the subject matter of the Compact. Green v. Biddle, 21 U.S. (8 Wheat.) 1, 89 (1823); see also Hinderlider v. La Plata River & Cherry Creek Ditch Co., 304 U.S. 92, 108 (1938); West Virginia ex rel. Dyer v. Sims, 341 U.S. 22, 28 (1951); Alabama v. North Carolina, 560 U.S. 330, 334 (2010) (applying contract law principles to Compact interpretation).

In the case of the Interstate Commission for Adult Offender Supervision (ICAOS), member states agree to a binding Compact governing the movement of offenders across state lines. The ICAOS is not discretionary; rather, it binds the member states, state officials (including judges, court personnel, and probation/parole authorities), and citizens to the Compact requirements that determine the circumstances, procedures, and supervision applicable to interstate transfers. See, e.g., M.F. v. State Exec. Dep’t, 640 F.3d 491, 497 (2d Cir. 2011) (stating, “The Compact is an agreement among sovereign states.”). Doe v. Pa. Bd. of Prob. & Parole, 513 F.3d 95105-106 (3d 6 Cir. 2008) (stating, “Once New Jersey granted permission for Doe to return to Pennsylvania, Pennsylvania was required to assume supervision over Doe and to treat him as in-state offenders. The Commission has not done so and in treating Doe and other out-of-state parolees differently, it violates its own agreement failing to do precisely what it promised . . . .”). Failure to comply with the Compact can have significant consequences for a non-complying state, including enjoinder from taking actions in contravention of the Compact. See, e.g., Interstate Comm’n for Adult Offender Supervision v. Tenn. Bd. of Prob. & Parole, No. 04-526-KSF (E.D. Ky. June 13, 2005) (order granting permanent injunction) (stating “[T]he defendants, their respective officers, agents, representatives, employees and successors, and all other persons in active concert and participation with them, are hereby permanently restrained and enjoined from denying interstate transfers . . . .”). In short, the ICAOS and its rules do not create a recommended process but rather a compulsory and binding process for applicable cases.