4 Interpretation and modi fi cation
4.4.2 Subsequent practice as justi fi cation for
What happens when there is a claim that the law has changed, because the states parties to a treaty have in their application of the treaty seen the matter in a way that is different from the text of the treaty? Such a claim seems not to have been formulated in the judgment in the Namibia case regarding the ‘concurring votes’
requirement of Article 27(3) UN Charter.
[T]he proceedings of the Security Council extending over a long period supply abundant evidence that . . . the positions taken by members of the Council, in particular its per- manent members, have consistently and uniformly interpreted the practice of voluntary abstention by a permanent member as not constituting a bar to the adoption of resolu- tions. By abstaining, a member does not signify its objection to the approval of what is being proposed; in order to prevent the adoption of a resolution requiring unanimity of the permanent members, a permanent member has only to cast a negative vote.222 This statement seems nothing less than a claim of change through subsequent practice.223 How could a vote of abstention – not silence – possibly be interpreted as a concurring vote? The Court’s wording, ‘signify its objection to the approval’, hints at the real theoretical difficulty. How can one presume consent when the point of a vote on a draft resolution is to make the choice of the members of the Council explicit, rather than implied? States members of the Council do not have to signify an objection to the approval; they have to approve, or object to, the proposal. The text of Article 27(3) UN Charter seems clear on this point – the meaning given by the Court in Namibia is not within the frame of possible meanings. The nine affirmative votes required shall include the concurring votes of the permanent members. To concur requires explicit action. Even though such an interpretation would make a great number of resolutions invalid under Charter law and might therefore rightly be called unrealistic or even destructive, adopting the Court’s meaning would constitute a change in the law.224
Grave doubts can be voiced about the lawfulness of subsequent practice changing treaties in international law. There are several approaches to justify this
222 Namibia (1971) supra note 55 at 22.
223 Karl (1983) supra note 125 at 234; Ress (2002) supra note 55 at 30 (MN 33).
224 For a thorough analysis of the situation under Article 27(3) UN Charter see: Bruno Simma, Stefan Brunner, Hans-Peter Kaul, Article 27, in: Bruno Simma (ed.), The Charter of the United Nations. A commentary (2nd ed. 2002) 476–523 at 493–501 (MN 46–74).
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possibility. Weighty theoretical arguments can be brought to bear against each of them, despite their valid claim that without such informal modification of treaties the workability of the international legal system could be endangered. However, one line of reasoning needs to be dispatched before we enter the substantive discussion, namely that the facts directly change the law without the need for an authorisation by the legal order. Scholars making this argument usually point out that change actually has happened through subsequent practice; this quote from Salo Engel exemplifies this presumption: ‘[I]n the daily practice of Members and organs, the Charter has undergone far-reaching changes even without the adop- tion of formal amendments.’225 This proposal is a petitio principii, for to prove that change can happen because change has allegedly already happened is begging the question of whether change can happen. This argument also transcends the Is–Ought duality. The acts of the subjects of law seem to be determining the law applicable to them at every moment and without the law’s authorisation. If thought through, breaches of treaty norms would not merely be the basis for new law, but would become a theoretical impossibility, because the subject’s every action determines anew what is law. This leads to the dissolution of the idea of law as norms, as an ideal, as something to measure behaviour upon.
Scholars making this kind of argument are, in the end, not lawyers, but political scientists:
For as regards nature, experience presents us with rules and is the source of truth, but in relation to ethical laws experience (alas!) is the parent of illusion, and it is in the highest degree reprehensible to limit or to deduce the laws which dictate what I ought to do, from what is done.226
The legal maxim ex iniuria ius non oritur227 is not applicable here and cannot be used against subsequent practice. It is irrelevant whether the actions the meta-law des- cribes as law-creating are violations of the norm to be changed (see Section 3.2.6).
There are two main lines of attack to justify the modifying power of subsequent practice to treaties. Either subsequent practice is evidence of a subsequent tacit treaty which would (partially) supersede the formally concluded treaty, or it forms part of a subsequent customary international law norm which would derogate from the treaty. The first argument will be discussed in the remainder of this section, while the difficult question of the relationship of customary international law to international treaty law will be discussed in Section 4.4.3.
225 Engel (1965) supra note 205 at 108.
226 ‘Denn in Betracht der Natur gibt uns Erfahrung die Regel an die Hand und ist der Quell der Wahrheit; in Ansehung der sittlichen Gesetze aber ist Erfahrung (leider!) die Mutter des Scheins, und es ist hửchst verwerflich, die Gesetze ỹber das, was ich tun soll, von demjenigen herzuneh- men, oder dadurch einschrọnken zu wollen, was getan wird.’ Kant (1781, 1787) supra note 30 at A 318–319, B 375 (translation John Miller Dow Meiklejohn).
227 E.g.: Hexner (1964) supra note 55 at 129. Hans Kelsen agrees that it is beside the point to argue about the legality of law-creating acts: Hans Kelsen, Recent trends in the law of the United Nations. A supplement to ‘The law of the United Nations’ (1951) 912.
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As far as the possibility of change in a treaty through subsequent practice is acknowledged and its judicial basis discussed, a justification as a subsequent and informal agreement is by far the most popular:228
If the masters of a treaty [its parties] are agreed, they are neither bound with respect to a treaty’s content in its interpretation, application or development . . ., nor do they have to observe rules of form and procedure. . . . If all parties to a treaty agree, they can modify or end a treaty explicitly or tacitly.229
The problems with the contractual theory are multifarious and start with the act of will as necessary condition for all positive law-making. Any contract is a meeting of wills and so it is in international treaty law. However, if the treaty is tacitly concluded, how do we prove that this meeting of wills has taken place and that the act of will required to make it a positive treaty has occurred?
The behaviour of persons can be interpreted in many different ways and it is unlikely that similar behaviour by multiple persons – a pattern of behaviour (Section 3.2.5) – evidences a meeting of wills by the states parties concerned.
Practice would be relegated to evidence of the real agreement230 and not as the legal foundation for change itself.
One answer to this would be to presume from the parties’ uniform subsequent practice that they had the requisite will. Karl agrees that we should accept real existing will as ‘guiding principle’, but for him what counts is not the actual will, but the social significance of typical objective behaviour, the impression made on the other subjects of law. For him, the basis of tacit treaties is the protection of trust (Vertrauensschutzprinzip). Trust worthy of protection is protected by doctrine by construing a legal act through a ‘quasi-liability’ (haftungsartig).231 However, this construct is based on a fiction that replaces law. Positive regulation is needed to create a ‘silence gives consent’ situation and if there is no such regulation, the opposite applies. Contrary to Karl’s argument that ‘assent is the most natural interpretation of silence where all circumstances would lead one to expect pro- test’,232 consent is not natural even where the circumstances would require explicit
228 Amerashinge (1995) supra note 63 at 200; Bernhardt (1963) supra note 4 at 126–127; Bernhardt (1967) supra note 199 at 498–499; Bernhardt (2001) supra note 198 at 16–17; Fitzmaurice (1958b) supra note 10 at 212; Karl (1983) supra note 125 at 268–313 (one possibility inter alia); Ress (2002) supra note 55 at 32 (MN 39); Waldock (1965) supra note 32 at 61 (para 32).
229 ‘Die Herren des Vertrages sind, wenn sie sich einig sind, bei seiner Auslegung, Anwendung und Fortentwicklung weder inhaltlich gebunden . . ., noch müssen sie Form- und Verfahrensregeln beachten. . . . Wenn alle Vertragspartner ỹbereinstimmen, kửnnen sie sowohl ausdrỹcklich als auch konkludent den Vertrag modifizieren oder auch ganz beenden.’ Bernhardt (2001) supra note 198 at 16–17. See also Aegean Sea Continental Shelf (Greece v. Turkey), Jurisdiction, Judgment of 19 December 1978, ICJ Reports (1978) 4, Dissenting Opinion Stassinopolous at 72 (para 3).
230 Karl (1983) supra note 125 at 274.
231 Karl (1983) supra note 125 at 271–273.
232 ‘Zustimmung ist noch immer die natỹrlichste Deutung des Stillschweigens, wenn alle Umstọnde einen Protest erwarten lassen.’ Karl (1983) supra note 125 at 276.
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protest. Acquiescence cannot be presumed, despite Karl’s operationalisation of acquiescence for the present situation.233 In creating obligations, states must be trusted to say ‘aye’ and not have scholars say ‘aye’ for them.
But the Pure Theory does not believe that international law is an informal legal order or that treaty change is not bound by formality.234 Because international law is a normative order and norms are a formal arrangement of claims to be observed, a hierarchy of norms, law is defined as form and without form it would cease to be norm. Therefore, despite the particularities of international law one cannot say that international law is nonchalant about informal modification.
Unless informality is explicitly, formally, allowed, the prescribed forms for changing the law have to be observed in order for change to be successful. A treaty can only be derogated by another treaty, not by informal consensus235 or by practice.
One could also argue that the formality of law requires a contrary act to derogate, i.e. an act of the same kind. A treaty can also provide for its change by a special procedure (Article 108 UN Charter). The law itself defines the means of changing the law and thus makes them formal, whereas in an informal order, the possible means of change are not defined a priori.
Even if we accept that another treaty has tacitly been created inter (omnes) partes, the question remains whether that later treaty can derogate from the former treaty, because it is a clash of treaty against treaty.236 Arguing that the implied will to conclude a treaty implies a will to derogate from the earlier treaty,237 especially where the former will was made explicit, while the latter is a scholar’s presump- tion, is not going far enough. It cannot be overstated how important and uncertain the matter is and how deep into theory the disagreement can be traced.
The role of logic in legal scholarship is at stake, a topic far too weighty to discuss in depth here. In 1960 Kelsen wrote that a legal order ought to be cognised by legal science as a meaningful whole, that is as an internally consistent unit and that therefore the principle of lex posterior derogat legi priori must be presumed to be included in an authorisation (by superior norms) to create law.238 In a posthumous book of 1979, the exact opposite seems to obtain: ‘lex posterior derogat priori [is] not a logical principle, but a principle of positive law.’239 If that principle should not
233 Karl (1983) supra note 125 at 276–281.
234 Karl (1983) supra note 125 at 74; Verdross and Simma (1984) supra note 50 at 424, 505.
235 Verdross and Simma (1984) supra note 50 at 505, 323–327.
236 Karl (1983) supra note 125 at 280.
237 Karl (1983) supra note 125 at 281.
238 Kelsen (1960) supra note 3 at 210 (Ch 34 e): ‘als in der Ermọchtigung mitinbegriffen angenommen werden’.
239 ‘lex posterior derogat priori [ist] kein logisches, sondern ein positiv-rechtliches Prinzip’; Kelsen (1979) supra note 47 at 103 (Ch 29 IV), 84–92 (Ch 27). Adolf Merkl had come to this conclusion early in his work, e.g.: Adolf Julius Merkl, Die Rechtseinheit des ửsterreichischen Staates. Eine staatsrechtliche Untersuchung auf Grund der Lehre von der lex posterior, 37 Archiv des ửffentli- chen Rechts (1918) 56–121, reprinted in: Hans Klecatsky, René Marcic, Herbert Schambeck (eds), Die Wiener rechtstheoretische Schule. Ausgewọhlte Schriften von Hans Kelsen, Adolf Julius Merkl, Alfred Verdross (1968) 1115–1165.
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be part of positive law and if both norms are on the same hierarchical level, a conflict of norms ensues, which implies that a legal order may contain two contradictory prescriptions.240 Accordingly, Wolfram Karl claims that the maxim is a norm of international law and a rule of interpretation.241 In Section 5.3 we will discuss the role and capability of the lex posterior rule in more detail.