Suffrage: use 30 votes in a day (bronze)
Vox Populi: use 40 votes in a day (bronze)
One of them should be removed because they are almost the same. I see no benefit in having them both.
If you vote on at least 10 questions, you can vote on 40 posts a day and get Vox Populi. If you are only voting on answers, you get Suffrage after 30 votes.
It appears that for some people, voting on questions is extremely hard (see this: Why aren't people voting for questions?). That is why there Vox Populi badge was added to encourage them to vote on questions, rather than changing rules for the older Suffrage badge.