There is no practical way to enforce restrictions on citizenship the way the OP is talking about. Any test is going to be biased, because the intent is to restrict (ie, make sure people fail the test if they don't know what you think they should know). The problem is that what makes a good citizen isn't something that's carved into stone...it's all up to interpretation. So, for example, you'll have liberals wanting a test that requires you to acknowledge civic duty, while conservatives will have a test where you have to agree with traditional values. Who decides what group has the "right" idea about citizenship?
I don't think you read the entire thread. How is literacy or basic math test biased? It's only biased against people who can't read or do basic math. It's not political.
