In the Declaration of Independence, Thomas Jefferson wrote that “Governments are instituted among Men, deriving their just Powers from the Consent of the Governed.”

As citizens, we give our consent by voting. In some states, not everyone is empowered to participate. According to a 2016 report by The Sentencing Project, more than six million Americans are unable to vote because they have been convicted of a felony. That’s one in every 40 adults.

Of the felons currently excluded from voting, about half have completed their sentences, a quarter are under probation or parole, and a quarter are still incarcerated, says Politifact. Federal law does not address voting rights for felons, so each state decides the issue on its own. As a result, the circumstances under which felons can vote, if at all, vary widely from state to state.

In Maine and Vermont, for example, felons maintain the right to vote while incarcerated. In 14 states and the District of Columbia, felons lose their voting rights while incarcerated but automatically regain them upon release. Twenty-two states automatically restore voting rights after a person has completed probation or parole. In the remaining 12 states, voting after prison is not so straightforward – it may require an additional waiting period or even a pardon from the governor. (The National Conference of State Legislatures has a full breakdown here.)

People who advocate restoring voting rights for people with felony convictions argue that it would help them re-assimilate into the community, noting that people are less likely to return to prison when they are meaningfully reintegrated into society. These advocates also point to the racial disparity in how communities are impacted by strict voting rules. Because people of color are disproportionately convicted of felonies, they are also disproportionately barred from voting. Their communities end up with less of a voice in public life.

Opponents, however, say that voting rights should only be restored after a process that determines whether or not a person has truly changed after paying their debt to society. Roger Clegg, President of the Center for Equal Opportunity, put it this way: “If you are not willing to follow the law, you cannot demand the right to elect those who make the law.”

As seen during the midterm elections, these rules are changing. Earlier this year, New York Governor Andrew Cuomo announced that he would consider pardoning felons who are on parole so they can vote. New York State law bars felons from voting unless they are on probation or have completed parole.

In November, Florida voters passed a constitutional amendment that would automatically restore voting rights to 1.4 million felons, excluding those with convictions for murder or sexual offenses. Sixty percent of voters supported the measure.

“This is an issue that transcends rural-urban-suburban divide. It transcends the partisan divide,” Neil Volz of the Florida Rights Restoration Coalition told NPR. “And it really is something that impacts all communities and all walks of life.”