<P> The sources have been influenced by a range of political and legal theories . During the 20th century, it was recognized by legal positivists that a sovereign state could limit its authority to act by consenting to an agreement according to the principle pacta sunt servanda . This consensual view of international law was reflected in the 1920 Statute of the Permanent Court of International Justice, which was succeeded by the United Nations Charter and is preserved in the United Nations Article 7 of the 1946 Statute of the International Court of Justice . </P> <P> Where there are disputes about the exact meaning and application of national laws, it is the responsibility of the courts to decide what the law means . In international law interpretation is within the domain of the protagonists, but may also be conferred on judicial bodies such as the International Court of Justice, by the terms of the treaties or by consent of the parties . It is generally the responsibility of states to interpret the law for themselves, but the processes of diplomacy and availability of supra - national judicial organs operate routinely to provide assistance to that end . Insofar as treaties are concerned, the Vienna Convention on the Law of Treaties writes on the topic of interpretation that: </P> <Dl> <Dd> "A treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose ." (article 31 (1)) </Dd> </Dl> <Dd> "A treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose ." (article 31 (1)) </Dd>

Which roman government body has to be in agreement before any law could be passed