TechTakes

US states aren't thought of as countries for good reason, but in the country's legal framework that kind of how they work -- just with a lot of work to make borders almost a non-issue, shared citizenship, shared economy, etc. This means that historically a lot of stuff that would be associated with a country (ID, driving permit, residency, military) either only happens at the state level; or happens at both the state and the federal level.

In the constitution the federal government is supposed to stick to it's lane as well: any powers which aren't explicitly given to the federal government are reserved for the states (10th amendment). Though in practice the federal government has a lot of powers.

That's the background and helps explain both the lack of a (compulsory) national ID and how there can be state level election shenanigans:

For national ID this was indeed a conservative bugbear. They were essentially worried about the government building a dossier on them or something. I don't remember the details it's been a long time: Conservatism 15 years ago was an entirely different beast than it is today. It's kind of hard to even imagine if the conservatives still have the same fears today, if the liberals don't, or how it would actually play out. Congress being deadlocked for so long means it's hard to get a vibe on how things would shake out if they started actually passing lots of laws again.

Oh yeah did I mention congress is deadlocked? This both means that the US is essentially operating on decades outdated laws, and that the legislature's infighting has lead to a power vacuum that the executive and judicial branch have slurped up (which helps explain the current Elon Musk mess)

Anyway election shenanigans: States were historically supposed to be, well, states as in closely aligned countries and this was all set up in the days before fast and easy long distance travel and communication (did I mention America is really big?). This means that each state runs it's own election (which it can do in any legal way it pleases). The outcome of the election is one or more electors, and those electors are who actually send in their choice for president. There have been cases of "faithless electors" who vote for someone besides the party they represent. Oddly this hasn't really been seen as a big deal (since the parties choose the electors they tend to be pretty loyal).

The point of the previous paragraph is this is a mess. Like a real mess. It's law that made some sense 200 years ago (and maybe not even, they were kinda #yolo-ing the constitution at the time) but is really dated. This means there's lots of room for shenanigans. Can a state legally disqualify voters? Maybe? Sometimes? Kinda? They're not supposed to be like racist or anything, but determining that depends on a lot of details and shifting supreme court rulings.