Desuetude of International Treaties, Beyond 1969 Vienna Convention

Desuetude of treaties in International Law means that a treaty is useless in specific periods of time and there appears a contrary custom against the treaty. Since the said treaty and the contrary custom cannot be performed simultaneously, the treaty will no longer be in use and the treaty will such be terminated. Although the Vienna Convention on the law of treaties, 1969 has not considered the desuetude of treaties as a way of termination, legal doctrines, case law and the state practice have added this to the causes of termination. Since the custom as one of the sources of international law bears the same position as treaty, it seems that, if the custom is formed correctly and in conformity with the required conditions, the treaty can be challenged and incapacitated encountering with such a customary rule. This may be justified with the implicit consent of the relevant subjects of international law.