International law and national law difference

Rarely.
Individual nations have the guns, and international forces only have the guns loaned to them.
So unless the international law has the backing of other nations/nation, the national law wins.
And of course in most of the other cases, it is really only a different set of national laws that win.

The main difference between international and national law is that international law regulates external relations between two or more countries by the signing of treaties and agreements concerning trade, war, the sea or oil, whilst national law or domestic law is applied within the boundaries of a country and is created in accordance with the constitution of the state.

National law is conditioned by the fundamental principle or rule that state legislation has to be obeyed, while International Law is conditioned by the principle “pacta sunt servanda” i. agreements between states are to be respected—which leaves International Law helpless as to the implementation of its rules and regulations over the ..

National law, which is often referred to as domestic law, are those laws that exist “within” a particular nation (State)

National laws are also recognized as the expression of the State itself, since it emanates from the local authority, which could be the law making institution, such as the United States Congress or the French Parliament

While national law primarily governs relations between private parties inter se, traditionally, international law concerned itself exclusively with the mutual relationship between states

What is the difference between national and international resources? What is the difference between international and national days?