Voting Rights Act: Questions

Why do you think this act, which implicitly exists to protect African American voting rights, mentions that a sixth grade education from the Commonwealth of Puerto Rico is fine in determining voting eligibility?
Why, in good conscience, do you think the Supreme Court stripped out key protections from the Act?
Should individual states be allowed to set their own voting requirements for national elections, or should there be a unifying set of laws across state lines?
Do you think this act has aged past being useful?
Why do laws even need to be put into place to reinforce existing laws?