Statement by Legal Adviser Retzlaff in the 6th Committee on Treaties over time
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Germany welcomes the inclusion of the topic “Treaties over time” into the work-programme of the ILC and commends the study group on the progress achieved in this year’s session.
The topic “Treaties over time” is of considerable practical importance. Subsequent agreements and subsequent practice are characteristic features of international law. Subsequent practice in the application of a treaty reflects the – possibly evolving – understanding of the parties as to the meaning of the treaty and is most important for the interpretation of a treaty as a whole. Since the majority of treaties are intended to govern the relationship between the parties over a long period of time, it is essential to adapt the interpretation of a treaty to changing circumstances and subsequent developments in order for the treaty to remain a flexible instrument of international law.
Whereas the jurisprudence of international tribunals provides significant guidance, a closer look at State practice regarding the interpretation and subsequent practice of treaties is of utmost importance, as it is first and foremost States which enter into treaties and decide on their application on a day-to-day basis. As long as subsequent practice is agreed on and does not become controversial, courts and tribunals will not even know about it.
To fulfil the parties’ need for legal certainty when executing a treaty, Germany sees the work of the study group as a fundamental step towards establishing manageable and predictable criteria for this mode of interpretation.
We look forward to continuing the exchange on this topic.