When interpreting the words of a treaty, the starting point is the ordinary
meaning of the terms of the treaty.52 The language in a treaty should be given its
normal and natural meaning, the interpretation that is standard and
commonplace. The "ordinary meaning" rule of statutory interpretation is rooted
in the assumption that the drafters intended words to have their common, usual
and normal meaning unless a contrary meaning is given. The ultimate goal of
treaty interpretation is to discover which obligations, rights and responsibilities
the parties to the treaty intended to sign themselves up for. Ascribing the natural
meaning to language to discover the likely intended meaning of that language is
therefore a reasonable and useful exercise regardless of whether or not it is
prescribed by the Vienna Convention.
The object of our inquiry is not a specific word or even a particular phrase,
but rather a whole sentence. Specifically, we are seeking to clarify whether and to
what extent States Parties intended to sign themselves up for mandatory
transnational obligations to establish prevention programs in countries of origin.
In examining the ordinary meaning of 9(4) it is useful to separate the provision
into its distinct parts, and examine the natural or normal meaning of each part.
1. "States Parties shall take or strengthen measures"
When "shall" is used, it indicates a mandatory obligation. "Shall" imposes
an imperative to take or strengthen measures. If the drafters intended for the
requirement to "take or strengthen measures" was optional, then "should,