The US is run by the constitution. Its the set of rules the country agreed to abide by and in actuallity is the country. It did not exist until it was ratified and pretty much does not when its violated as a matter of policy. When interpreting there is actually a large body of writings from the founding fathers on how the various parts came to be. The philosophy that built the country. Its pretty clear that power originates with the people who are represented in the state and federal government. If further clearly says when something is unsure it is in the realm of the states or the people directly. In particular it says states decide how to run their elections. Due to the fact people can move around and between states the states started requiring registration for elections so they could verify the person does indeed reside in the state and locality where they are eligible to vote in the elections. Coming from the eu do you show an eu id or one from the country? In many ways the states are like countries in the eu. Essentially the us has a much stricter and local process so that only people eligible to vote do so. Even within the state the elections are largely run by the county or in the case of large cities the city. The state essentially just acts as oversite for the localities and collects the vote totals. Its basically so anti american to have the federal level involved as to be treasonous. Its disturbingly part of facist attacks on our checks and balances. Its a massively bad thing.