Breaking with the Past 231unclouded by moralistic or natural- law sentiments as to what the practice of
states should be.
Th e second distinctive feature of the empirical variant of positivism was a
focus on sanctions. Th is arose as a solution to a serious problem that bedev-
iled the empirical positivists: how to distinguish a true rule of customary law
from a mere common practice of states— that is, from mere “usage,” in the
common expression. In principle, there were various possibilities. But the an-
swer that was most commonly (though not unanimously) settled on was that
the presence of a sanction is the hallmark of a rule of law. If a state departs
from a practice that is merely a usage, then it will simply be permitted to go
its own way as it wishes. But if it departs from a rule of law, then it exposes
itself to sanctions from other states— specifi cally, from any state that suff ers
an injury from the breach.
Th is approach to customary law, it will be observed, was in keeping with
Austin’s emphasis on sanctions as an essential feature of law. It was only
necessary for international lawyers to take a broader and more relaxed view
of what counts as a sanction than Austin had. Austin, it will be recalled, had
insisted that a sanction must be a punishment infl icted by a sovereign upon
its subjects. International lawyers maintained that a sanction can consist of
any kind of negative reaction to a breach of a rule. It could comprise, for
example, a reprisal action, or a rupture of diplomatic relations, or the de-
nunciation of a treaty. At its most extreme, it could be a resort to war. Th e
important point, though, is that international lawyers recognized that, with
self- help mea sures as the principal reaction to wrongdoing, the sanctioning
power of international law must be understood to be diff used throughout
the legal system and not concentrated in the hands of a single entity, as Aus-
tin had demanded.
Th e Common- will Variant
At the core of the common-will variant of positivism was the belief that
rules of international law are the fruit of agreements between states. A rule
of law, according to this theory, is generated by the conjoined wills of two
(or more) states, most obviously in the form of a written treaty. Treaties were
accordingly regarded as the archetypal source of international legal obliga-
tions (instead of custom in the case of the empirical school).