The McMahon Line was considered by the British and later the independent Indian government to be the boundary; however, the Chinese view since then has been that since China, which claimed sovereignty over Tibet, did not sign the treaty, the treaty was meaningless, and the annexation and control of parts of Arunachal Pradesh by India is illegal.
McMahon-linjen blev betragtet af briterne og senere den uafhængige indiske regering for at være grænsen; dog har den kinesiske opfattelse siden da været, at eftersom Kina, som hævdede suverænitet over Tibet, ikke underskrev traktaten, var traktaten ugyldig, og annektering af og kontrollen med dele af Arunachal Pradesh af Indien er ulovligt.