418 Between Yesterday and Tomorrow (1914– )in favor of “a consensualist or voluntarist approach to international law.”
As such, he was a staunch opponent of a drift toward majority rule in inter-
national law, which he denounced as a “pathological phenomenon.” He
insisted that the function of international law remained— as it always had
been—“to ensure the co- existence... and the cooperation of basically dis-
parate entities composing a fundamentally pluralistic society.” Th e com-
munity of states was described by him as “a society of juxtaposition,” with
the right of states to take diff erent paths from one another being a funda-
mental feature of state sovereignty. “[T]here can be no question,” Weil
averred, “of some ‘international democracy’ in which a majority or repre-
sentative proportion of states is considered to speak in the name of all.”
Opposed to this is the legislative theory of custom, which had the strong
support of Kelsen. Another supporter was the French writer Michel Virally,
who taught at the Graduate Institute of International Studies in Geneva and
later at the University of Paris. Customary law, Virally contended, is gov-
erned by a principle that he labeled as “opinio juris communis”— meaning
communal legal opinion, or the general consensus of states. He described
customary law as “the translation in terms of law of the spontaneous activ-
ity of the social body.” What is looked for, therefore, is the presence or ab-
sence (as the case may be) of a general or collective consensus on the part of
states as to the existence of a law, and not the consent of each state individu-
ally. Whether such a general consensus is present or absent is a question of
fact, to be ascertained by careful observation of state practice, which Virally
asserted to be “the central element” of customary law.
What is at stake in this conundrum may be stated simply. According to
the legislative view, the majority of the states binds the minority, in the way
that laws adopted by a majority of a legislature are binding even on those
who oppose them. On a contractual view, in contrast, customary laws bind
only those states that actually participate in or consent to the rule, leaving
the dissenters free to go their own way. Voluntarist lawyers are, eff ectively
by defi nition, committed to the contractual thesis. Empirical lawyers could
go either way without undue diffi culty.
Th is interesting— and fundamental— question as to the nature of custom-
ary law remains unresolved. Th is is partly because at least some of the em-
pirical positivists have given their support to a major caveat to the legislative
position. Th is involves accepting the majority rule thesis in principle— but