Immigration policies refer to a national sphere because it affects the country as a whole, so all changes and the formulation process of an immigration policy must come from a national sphere and the whole country needs to live by these laws and policies.
National. The national government is responsible for policies involving international plans that affect the nation (such as immigration, military, and taxing decisions)
the legislative branch (congress, Senate and the house of representatives) make laws, the judicial evaluates the laws while the executive carry out those laws
