432 Between Yesterday and Tomorrow (1914– )Nevertheless, it is possible to identify two specifi c signs of the solidarist
outlook in postwar international law. Th e fi rst was a provision in the Vienna
Convention on the Law of Treaties on what are called “peremptory norms”
of international law (or ius cogens, for those still wedded to Latin). Th ese are
customary rules or general principles of law that override the wills of indi-
vidual states, in the sense that, if two states agree to a treaty that is contrary
to a peremptory norm (such as an agreement to discriminate against a named
racial or religious group), then the treaty will be automatically void. Pe-
remptory norms, therefore, are expressions of general community values that
trump agreements between individual states.
Th e other specifi c indication of the solidarist perspective in action was
provided by a World Court judgment in 1970, which stated that there is “an
essential distinction” between two kinds of obligation. Th e fi rst kind com-
prises duties owed to a specifi ed state or group of states. An ordinary treaty
obligation falls into this category. Th e second kind of obligation is owed to
“the international community as a whole”— with the crucial implication
that any and every state is allowed to make a legal claim in the event of a vio-
lation. In this category of general community duties (as they might be de-
scribed), the Court identifi ed the prohibitions against aggression and geno-
cide, as well as (more broadly) “the principles and rules concerning the basic
rights of the human person.”
Th ese two concepts— of peremptory norms and of obligations owed to the
world at large— are of potentially far- reaching character, suggesting the ex-
istence of a superior community will that takes pre ce dence over the “ordi-
nary” wills of states. It cannot be said, however, that either of these notions
has actually made any major concrete contribution to international law.
Perhaps an opportune moment has simply failed to present itself. It may be
that potentially transformative concepts will loom large in the international
law of tomorrow, even if their present- day role is a meek one.
A Th ird World Arrives
Th e idea of a three- tiered international system was not new. It has been ob-
served that, during the nineteenth century, international lawyers, following
in the footsteps of contemporary anthropologists, had posited the existence