Depends on the state, when I lived in Florida you had to be registered to a party to vote in their primaries. It varies all over. Some states you get a ballot with all of the names for the people in your party for primaries, some you can choose any member of any party, it shows that the states aren’t really as similar as we think they are, as the laws for most everything vary. Punch someone in one state, it’s a battery charge, in another it’s assault; which you may be able to get for yelling/threatening to hit someone. Get caught with an illegal substance, well the substance list changes by state, the volumes required for charges change, and the consequences vary. What counts as rape, what age you can marry… It goes on and on. Taxes change by city, county, and state.