The United States Constitution guarantees the right to vote for all adults. The 14th Amendment, Section 2, however contradicts this, in allowing disenfranchisement by the States, for "participating in rebellion, or other crime."
This is what empowers the States to make arbitrary conditions upon which they can take away voting rights from any citizen. Some States take those rights away for life. Other states allow prisoners to vote. In this way, these States are not United.
A plan should be made to either nullify the "other crimes" portion of the Amendment, or end disenfranchisement completely, at every level. A key part of being an American is the ability to have our voices heard, and a key part of that is voting.