As a European, the whole registering to vote thing is honestly one of the wildest parts of the US elections to me. It’s so unnecessary complicated and prone to errors/manipulation. I just have to show up with my ID, doesn’t matter if it’s for the EU parliament or the local city senate.

I see comments like this a lot. Most important and apparently most difficult for Europeans (and others but it’s almost always Europeans) to understand is that the US is a very large country, made up of 50 semi-independent states, each with its own government and laws-- about many things, not just elections. So that’s why things are more complex here–we’re not a small monolithic nation with one single, centralized government and set of laws that apply to everyone no matter where in the country they live.

Each US State runs its own elections; a person obviously can’t be allowed to vote in more than one state. Since people can move from one state to another at any time, and even have residences in more than one state at the same time (such as college students and well-off people), it’s necessary to register with the state you will be voting in, so that you are officially able to vote in that state and no other.