The United Kingdom consists of four constituent countries. From a constitutional point of view, each U.S. state exercises more sovereignty in its domestic affairs than any of those constituent countries. WEstminster could tomorrow disbad the Welsh Assembly and Sottish parliament. It would be unconstitutional for the federal government (in peacetime) to in any way dissolve the government of a state. A state law can be challenged in the judiciary, or the federal government may pass a law applying to the whole union which effectively nullifies a state law, but it cannot dissolve a state or alter its borders without the authorization of that state. Correct. A federation of sovereign states, and an arguable distinction without a difference from a purely constitutional point of view. The states are tighter bound under the Constitution than they were under the Articles of Confederation, but they are nonetheless largely internally sovereign in domestic affairs and institutions, provided their governments are republican in form and that the constitutional liberties guaranteed federally are maintained. Essentially, yes. Basically. And, before the civil war, Aericans travelling abroad would basically identify with their state if asked where they were from. In theory. Americans bon abroad are not necessarily citizens of a particular state until they move to one. The status of people in the insular areas is thornier, and being resident in a state if not a U.S. citizen does not confer state citizenship. Citizenship and immigration are Article I powers of Congress in its establishment of a uniform code of naturalization. Precisely.