Should you have to pass a test to be allowed to vote? People tend to freak out when I sympathetically consider this possibility. It not fair! Who would write the test? Wouldn't it be discriminatory?!
The funny thing is that we already have such a test - for immigrants. You don't need to pass the citizenship test to get a green card; but if you want the right to vote, you need to answer 60% of the questions correctly. And unlike this sample test, the actal test is not multiple choice. (For more questions, go to page 60 of this Guide to Naturalization).
I bet that at least half of Americans would fail this test if you gave it to them today. I'd further bet that if you had to pass the test to vote, most of the people who initially failed wouldn't be willing to hit the books to get a second chance. Our civic religion may say that the "right to vote is our most precious right," but few people literally believe it. And it's a good thing, too.