One thing I've never understood is why Arizona is required to pre-clear. There are barely any black people there to disenfranchise, and there certainly weren't any when the law was passed. Was there some sort of discrimination against Hispanics going on there?
Yes. The test for whether a jurisdiction would be subject to preclearance was the percentage of the voting age population that was registered to vote. With a requirement for English language literacy keeping Hispanics from registering, Arizona fell subject to it. It's also why three of the New York City boroughs are subject to preclearance. The electoral law in 1964 kept many Puerto Ricans who had moved there from voting in New York.
That's really interesting! I had no idea!