 From the point of view of domestic law of each state, international law is not a fact, but it is law. And this is simply because states participate in the creation of rules of international law through their organs and according to their respective constitutions. It would be ridiculous from the point of view of every state to consider that the rules of international law the state had to develop would simply be facts and not rules of international law. After all the state wanted those rules to exist as rules of international law and the state knows very well that if it decides to be bound by them it will have no legal choice but to comply with them under international law. However if international law is law from the perspective of domestic law it is law that is part of domestic law or is it law that remains separate from domestic law. Those are two ways of looking at international law as law. From the perspective of domestic law either you consider that international law and domestic law form together one unified legal order as it were that international law is part of domestic law automatically and that it prevails over domestic law in case of conflict. And that view is called monism. Or you consider that international law is law but that it remains distinct from domestic law that they both exist as law but that international law remains separate from domestic law and only penetrates domestic law and interacts with it according to the conditions laid out in domestic law itself. And that second conception is called dualism. The truth of the matter is that pure monism or pure dualism do not really exist in the real world. True, some states are more monist or more dualist than others but each rather monist state has a dose of dualism and each rather dualist state has a dose of monism. And for instance, and I'm sorry to refer to an example I'm more familiar with, for instance Belgium is traditionally considered as a rather monist state but treaties do not penetrate the domestic Belgian legal order without being approved by the parliament which is an element of dualism. If they are not approved by parliament treaties ratified by the government are internationally binding on the state but they remain outside the domestic legal order. They have no effect in Belgium and cannot be applied by the Belgian courts. And to take the United Kingdom which is traditionally considered as a dualist state in the United Kingdom as in most states it is said that custom international law is part of the law of the land. In other words, that custom international law applies in English law and is a source of law in English law and that's an element of monism. Now this diversity points to something which is essential. International law does not compel states to be monist and it does not prohibit them to be dualists. Actually there is no rule of international law on the matter and states remain absolutely free in that regard. Of course if a state decides to adopt a rather monist approach of its relationship with international law and if it decides also that in case of conflict between domestic law and international law the latter shall prevail then that state is statistically less likely of being found in breach of international law. But the state is perfectly free to prefer to stick with a dualist approach even at the risk of being more often found guilty at the international level of being in violation of its international law obligations. But the state may prefer to see its constitution or its laws prevail over its international law commitments. True, that is absolutely not acceptable from the point of view of international law and it would result in the state being found responsible for a breach of its international obligations because from the point of view of international law again not even the constitution of the state might serve as an excuse for not implementing international obligations. But the fact of the matter is that being a dualist is not as such a violation of any international obligation, it is only the implementation of a dualist stance that leads to breaches of specific international obligations.