If you live in the states on the map below* with same-day voter registration, you can still vote even if you haven't registered to vote! (*early voting has already ended in NC and NY)
Another note that New York is currently even weirder having only allowed same day voter registration on a single day of early voting rather than the entire period unlike North Carolina
Many of states on that map have started adopting it only more recently, so there's been a push to increase it! If it's not in your state, consider writing to your local state legislature representative to push them to pass laws for it next election!
It managed to get through in red Utah in 2018, so don't think it's necessarily a lost cause even if you are in a red state (though yes they are more resistant to it)
They do require a valid ID, though, which can be a problem for some people. I don't know what their requirements are for "ID", but it's probably a driver's license or passport, or state-issued ID. These have all been shown to be barriers for certain groups of people.
In states that have voter registration, proof of identity often accepts more broad documentation: birth certificates, or other documents acceptable for what you'd need for a DL.
So, it's cool for everyone who has a driver's license, or a passport. Not so cool for folks who don't drive (because of a handicap, for instance). Convenient for many people, but not "based". Requiring ID at voting time is a tactic used to disenfranchise groups of people. Young urban voters, for instance, who may not yet have needed a license.
I live in Europe and only need to prove citizenship with an ID to vote. I thought all the "registration" talk I've been hearing was party-based to prevent Democrats from sabotaging Republican primaries by voting for their outsiders and vice versa, not for the actual election.
Yeah no it's for any kind of popular vote, local, state, and federal. It's insane
What's funny is that it's incredibly easy to change parties, so if there was a combined effort to alter the outcome of the party's nominee, it would probably work. In fact, you could argue that's what happened in the early 20th century.
To make a long story short, a lifetime or two ago, Democrats were the right leaning "small federal government" party, and Republicans were the ones pushing for social change, in fact, Abraham Lincoln (who was a crucial figure in abolishing slavery in the US) was the first Republican ever elected president.
Anyway, from the late 1800s and into 1900s, democrats began electing more progressive candidates (Roosevelt is a big example) who were more on board with things like equality and government assistance programs than the Republicans, who, one could argue, began to fall back into the older ways of religion and "family values" .
p.s. I wrote this in the middle of a calculus lecture so it might not be the most comprehensive history. If anyone wants to add or correct anything please do so
p.p.s I also now realize you probably weren't asking for a breif on the history of politics in the US lol