In international law, the word "doctrine" is generally applied to a state's successful claim to some special prerogative presented thereafter as a permanent part of the foreign policy of the state evincing the doctrine. Such claims are made constantly in international politics as part of the continuous process of claim, counter-claim, testing of relative resources and intensity of demand, and, finally, decision by accommodation, compromise, or imposition. Claimants often try to anticipate success by immediately labelling their claims a doctrine. But names are not decisive. Many such claims are characterized by others as unlawful and successfully resisted. However, when the intensity of interest and effective power of the claiming state are such that, whatever the general reaction, it is plain that its claim will be made into controlling practice, the assertion can no longer simply be dismissed as unlawful by others. Rather, it is widely accorded the more ambiguous quasi-legal term of "doctrine." This reaction is not an abnegation of law, but is part of the tendency of the international legal system to remain minimally relevant by accommodating to the unyielding realities of effective power.
W. M. Reisman,
Old Wine in New Bottles: The Reagan and Brezhnev Doctrines in Contemporary International Law and Practicet,
Yale J. Int'l L.
Available at: https://digitalcommons.law.yale.edu/yjil/vol13/iss1/8