Restrictions imposed by domestic law do not excuse a State from due performance of international legal obligations. Either in observance of this principle, or as a sheer coincidence, most States have a framework of domestic legislation that, to varying degrees, would facilitate compliance with international legal obligations. But, as Wallace observes, ‘there is no universal practice stipulating how States should incorporate international law into their domestic legal systems and it is a State's perception of international law which determines the way in which international law becomes part of municipal law’.