The national coat of arms, and not the royal coat of arms, is used by the Norwegian parliament (Stortinget). Norway is a monarchy in accordance with the country's constitution and the constitution is decided by the parliament (Stortinget) and its member representatives elected by the people. The Norwegian king is a king with his legal position defined by the constitution and the monarch is a not sovereign with powers over, or at any higher level, than what is given him by the constitution. I think that is the same situation as in most modern European monarchies.