International law establishes its own distinctive framework dealing with both the sources of international law and how that law deals with the relations between States. Accordingly, treaties regulate certain relations between States at either a multilateral or bilateral level and the obligations created under these treaties create certain levels of State responsibility by the treaty parties to act in good faith. While the international law frameworks regulating the relations between States are relatively well developed, the role of international law at a municipal level is equally important. This can be illustrated in various ways.
Human rights conventions recognise certain rights for citizens of a State. In some instances these rights may also reflect constitutionally entrenched rights of citizens. Often, however, these rights are both distinctive and universal in nature and may not be reflected in municipal legal systems. The issue that then arises is how to translate the international human rights obligation contained in the convention into municipal law. Likewise, under environmental conventions State parties may have obligations to preserve and protect certain designated wilderness areas. To properly give effect to these obligations it may become necessary to designate a protected area or park under municipal law. One consequence of this may be that future development of the area will be constrained as a result of municipal law seeking to give effect to the terms of an international convention. Further, the United Nations (UN) and its various organs may create obligations for member States through Security Council resolutions that impact at both the international and the national levels, thereby raising issues as to how these obligations are to be given effect domestically so as to ensure that the State remains in compliance with its international obligations.
The challenge then for both international law and municipal legal systems is how the international law obligation becomes recognised at the municipal level so that both rights and obligations are created not only for the State and its institutions, but also for citizens and business entities. Occasionally the constitution of a State may indicate precisely what status international law has within that municipal legal system.