Panel 2.2 / Faultlines and Weak Spots in the Edifice of CIL
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Whence the Legitimate Authority of Customary International Law: to Honor State Consent, or Legitimate Expectations – or Both?
State consent has long been assumed to be the central and even sole source of legal
validity of international law (IL), by the ICJ and International Legal Positivism.
This centrality of state consent, has been challenged for several empirical, conceptual
and normative reasons, especially but not only for customary IL (CIL) This paper explores
such criticisms to reconstruct claims to legitimate authority on behalf of IL in general, and
for ICL in particular: Whence any claims of the sources of IL to offer reasons for judges
for interpretation of IL, and for compliance constituencies to defer to judgments of
international courts, to act any different?
An aim of this paper is to explore whether and how arguments for the centrality of state
consent can provide (partial) support for ICL’s claim to be a legitimate authority, and shed
light on why state consent is neither necessary nor sufficient to give rise to legally binding
obligations – yet why state consent may sometimes be relevant.
Section 1 explores challenges to the current centrality of state consent. States consent
is difficult to discern even for several formal sources (ICJ Statute Art 38) (– not to
mention law making by international organizations – Alvarez 2006 and international
courts, von Bogdandy and Venzke 2011). In particular, ICL, including norms of pacta sunt
servanda and jus cogens, are said to derive and develop from the practice of state. So
treaties may thus bind third parties (Vienna Convention Art 38, Pellet 2000, 37-38;
Meron). The criteria of state practice and opinio juris are not only unsatisfactory ‘nonmoralized social facts’ as evidence of state consent, but their vagueness leave judges
striking discretion – and are conceptually contested to boot.
Section 2 therefore identifies reasons to value state consent even when, and especially
when, “consent is falling out of favour” (Collins 2018). Reasons with varying scope of
application and weight include compliance, specification, reduction of domination and enhanced fairness. Such arguments help assess both the value of state consent and
proposed improvements. One aim is to identify the conditions, limitations – and
incompleteness of state consent as necessary or sufficient conditions for some of the
states’ legal obligations. These help identify any justification of such circumscribed state
consent for the legitimate authority of IL and ICL. Proposed reconstructions and
improvements presumably retain some functions for state consent, specified in light of
these reasons.
Section 3 starts to situate state consent in alternative broader normative accounts of
promise-keeping. In particular, the paper explores the normative premise of “what we
owe to other people when we have led them to form expectations about our future
conduct. “ (Scanlon 1990, 199-201, 208; MacCormick 1972) . This is certainly only one
normative requirement on behavior, and the social practice of promises including treaties
is only one of several means to create such expectations. Other behaviour, as part of
practices or not, can also create such expectations. Other overriding duties may hold
independent of any social practice.
Section 4 brings this account to bear on the roles and current conditions and scope of
state consent in creating valid obligations under IL, and on the claims of ICL in particular
– including its defining characteristics. Topics may include the norm that new jus cogens
norms retroactively void treaties (Vienna Convention art 64); a more plausible
reconstruction of ‘tacit consent’, why coerced peace treaties may still be legally binding,
etc.
Law and its Other: The Making of Customary International Law
My paper asks what the existence of customary international law means for the idea of
rule of law in international law. To this end, it will provide a theoretical critique of the
process through which customary international law is being created. The central claim is
that the production of customary international law needs to be seen – at least in effect
– as a continuous suspension of international law, for it provides a legal mechanism to
change or re-interpret international law through its persistent violation. It thereby
renders the rule of law in international law incomplete, subjecting international law to a
sphere of lawlessness.
The paper proceeds in three steps. Firstly, taking in account the legal conditions for the
emergence of customary international rules, I will examine the precise way in which
customary law systematically enables States to act in disregard of international law,
creating what can be called a realm where international law is absent. I will then, in a
second step, inquire how this coexistence of legal validity and suspension can be thought
of in detail. The challenge here is to develop a theoretical notion of custom that
appreciates the contradicting moments which arise from its legal doctrine, most
importantly the fact that international law instates legal rules and at the same time
provides a mechanism that calls for their violation, and the fact that it is international law
which suspends itself. International law, through a mechanism of its own, is at once valid
and invalid. To deal with these questions, I will draw on Carl Schmitt’s concepts of
sovereignty and the exception, Walter Benjamin’s critique of revolutionary and legalized
violence, as well as insights from poststructuralist theories of Jacques Derrida, Giorgio
Agamben and Niklas Luhmann, among others. The result will be an ontology of customary
international law that reveals how the process of customary international law production
gives rise and maintains a relation to its opposite. It will show that ‘behind’ the legal rules
on customary international law lies a social process that defies the limitations of
international law.
This implies further consequences for how we should think of international law in
general. With a view to examining these consequences, I will, in a third step, compare
the way that international law relates to its other through customary law to the way that
international law and even law in general relate to spheres of alegality, as well as reflect
on the character and function of customary law in international relations. Against this
background I will conclude that without significant alterations to the legal concept of
customary law creation which eliminate the reference to State practice, customary
international law will be a factor, inherent in international law, that undermines the
legalization of international relations.
The paper is part of an ongoing PhD-Project on the theory of customary law and the
right to self-defense, of which it will constitute the central theoretical chapter.
Particular vs General Rules: A Major Faultline for Customary International Law
Customary international law comprises general rules binding States generally, and
particular rules binding only a limited number of States. My paper focuses on what
particular customary law is, and on its relationship with general customary law. This is
not a marginal topic. I will suggest that the distinction is profoundly important to
customary international law. I will also suggest that the distinction is challenging to draw,
in part because of difficulties in interpreting State practice.
What is particular custom? A common view is that it is geographically confined – eg
arising among neighbouring States, or with regard to a matter falling within a certain
geographical area. Hence writers and jurists have spoken of “regional” or “local” custom.
Another view, recently endorsed by the ILC in its 2018 draft conclusions on custom, is
that particular custom need not be geographically confined: “there is no reason in
principle why a rule of particular customary international law could not also develop
among States linked by a common cause, interest or activity other than their geographical
position”.
This approach faces problems where State practice and opinio juris diverge. Suppose that
80 States recognise the immunity of incumbent Heads of State from foreign criminal
jurisdiction, and 60 States deny such immunity. The practice is too inconsistent to infer
a general rule. But might we infer a particular customary rule, at least among the 60
States? (And perhaps another particular rule among the other group of 80 States?)
The ILC’s response is that particular custom depends on a practice among “the States
concerned that is accepted by them as law (opinio juris) among themselves”. Its
commentary explains that “the practice must be general in the sense that it is a consistent
practice ‘among the States concerned’, that is, all the States among which the rule in
question applies”. Perhaps, then, no particular customary rules may be inferred in the
above example if each group of States (80 and 60) think that the rule applies to all States,
not just among members of their own group.
But how do we tell? How should we interpret State practice given that it is typically
vague or silent on this matter? Should interpretative presumptions be used and, if so,
how and why?
The ILC’s proposal raises further concerns. Suppose that a particular customary rule (as
the ILC understands it) emerges among 20 States, who do recognise this rule among
themselves. Later, 5 additional States begin engaging in practice that seems to align with
this rule; must each of the 5 be recognised by the group of 20 so as to establish a rule
“among themselves” (the 25)? And again, how is this to be inferred from the State practice
given that it is normally silent or vague?
TRICI-Law - The Rules of Interpretation of Customary International Law 