"Contra proferentem", a self-serving argument used by treatyists, is a doctrine of contractual interpretation providing that, where a promise, agreement or term is ambiguous, the preferred meaning should be the one that works against the interests of the party who provided the wording.

The unfortunate reality for treatyists is that there is no ambiguity in Te Tiriti (Original Maori Treaty of Waitangi).

The only ambiguity is that introduced by 1980s re-interpretations.

So if the "contra proferentem" doctrine is used on those 1980s interpretations, the preferred meaning should be the one that works against the interests of the party who provided the wording, which would be in those cases, against the interpretations provided by Hugh Kawharu and the Waitangi Tribunal.

The contra proferentem rule was created in Canadian law in 1952.