I think that while the intention is perhaps benign (wanting informed voters), the methodology of ensuring this would just be an endless struggle that get stuck

I think that while the intention is perhaps benign (wanting informed voters), the methodology of ensuring this would just be an endless struggle that get stuck in an eternal hell of "how do you do this in a way that is actually meaningful to the voting process without introducing biases or getting stuck in endless arguments about the tests?". While understanding the how and why of US Civics is important, it doesn't much illuminate or educate the average voter when it comes to relatively straightforward ballot items. Imagine a ballot item that is a small sales-tax increase to fund highway renovation for a city; the knowledge of US Civics isn't really necessary to understand that if it goes through, there will be construction to fix a highway, but things like grocery bills will be slightly more expensive. Civics knowledge isn't really necessary to help determine the voter's feelings about such a bill. I think one of the biggest issues is that a lot of times voters just don't know what is on the ballots or are unable to find lay person explanations for bills. When I lived in Washington, every election residents would be mailed a voter's pamphlet by the state. The pamphlet contained a state provided listing of every item on the ballots, what the cost/impact would be, the intended outcome, and then both proponents and opponents were afforded a small section (maybe 500-700 words) to explain their point of view on the item. The pamphlet was super useful, and I could see something like this helping to alleviate at least a little bit of the misinformation and lack of information that is persistent in voting, even if the majority of voters just throw it in the trash (which is what many of my friends and colleagues told me they did). It's a real shame that the pamphlet wasn't more popular, since it was pretty well done during the years I lived there. I wish more states would adopt it.