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ESZTER POLGÁRI
the existence of such a right was supported by the growing measure of common
ground that had emerged in the given area".?é
The case-law confirms that the Vienna rules are flexible enough to accommodate
the methods and doctrines invoked in the interpretation of the ECHR, and the
‘special character’ of the Convention” has not resulted in the development of
a competing interpretative framework; the Court merely puts emphasis on
effectiveness and a dynamic approach to the text over the traditional international
law principles of state consent and restrictive interpretation of state obligations.
SUBSEQUENT PRACTICE
Article 31 (3) adds further sources that need to be taken into account together
with the ‘context’ when establishing the ordinary meaning of a term. Subsequent
agreements and practice constitute “forms of authentic interpretation whereby
all parties themselves agree on (or at least accept) the interpretation of treaty
terms by means which are extrinsic to the treaty”.** As Villiger noted authentic
interpretation offers “ex hypothesi” the right interpretation and consequently
it is conclusive to the ordinary meaning.”” In the ECHR case-law subsequent
agreements contained in Article 31 (3) a) do not play a significant role, there is
no judgment that would refer to them beyond the citation of the Vienna rules.
Subsequent practice, on the other hand, has been invoked by the Court explicitly
and — as it will be explained below — implicitly more frequently.
In order to assess whether the case-law of the ECtHR is in harmony with
the VCLT’s provision on subsequent practice, a brief overview of the rule is
indispensable. ‘Practice’ itself covers a great number of positive actions, in public
international law it would simply encompass “what states do in their relations to
one another”.*! Some argue that subsequent practice must be consistent, common
and concordant,” and it has to be acquiesced in by other parties, otherwise it will
remain a supplementary means of interpretation under Article 32 of the VCLT.*
26 Ibid, para 137.
2” For an explanation of the peculiarities of the ECHR see for example: Ireland v. the United
Kingdom 5310/71 (18/01/1978), A25, para 239.
Mark E. Villiger, Commentary on the 1969 Vienna Convention on the Law of Treaties,
Leiden, Martinus Nijhoff, 2009, 429.
29 Ibid, 326.
3° VCLT Article 31 (3) c).
3 [rina Buga, Modifications of Treaties by Subsequent Practice, Oxford, OUP, 2018, 23.
3 Tan M. Sinclair, The Vienna Convention on the Law of Treaties, Manchester, MUP, 1984, 137.
33
28
Georg Nolte, First Report on Subsequent Agreements and Subsequent Practice in Relation
to Treaty Interpretation (19 March 2013), UN doc A/CN.4/660, para 118.
s 326 "