Why was the power to declare war given to the national government and not the state government?​

The excerpt is from the universal declaration of human rights. everyone is entitled to all the rights and freedoms set forth in this declaration, without distinction of any kind, such as race, colour, sex, language, religion, political or other opinion, national or social origin, property, birth or other status. –article 2, universal declaration of human rights this passage from the declaration is designed to a)ensure human rights for united nations members. b)explain how human rights violators will be punished. c)protect human rights of all people in the world. d)grant human rights to the world’s most powerful people.