50 percent of the US population are not required to, and do not, pay Federal taxes. These folks should not have the right to vote since they have no skin in the game. After all, they can just vote themselves money from a treasury that they don't contribute to. This is exactly backwards of how the country was founded since in 1776 we fought for no taxation without representation.
I don't think you lose your right to vote because you don't pay taxes. We didn't have income taxes until way past the founding.
I do think that our code is unconstitutional because having the top 1% pay what, 40%, 50% of the taxes violates fair and equal treatment under the law.