48 states prevent incarcerated felons from voting — hundreds of thousands of Americans refused their right to vote. 38 states prevent people on parole from voting, and 31 include people on probation as well. 4 states disenfranchise felons completely, even after their sentence has ended. Several states only reinstate voting rights after lengthy appeals, and many released felons aren't told they even have this right.
Disenfranchisement is simply one more way for politicians to sway election outcomes, and we can't stand for it any longer. Millions of Americans are deprived of the right to vote in the elections that affect them just as much (often even more) than any other citizen.
Not only does disenfranchisement bias election outcomes, but it is also another way top reinforces the stigma against convicted felons. After serving a sentence, felons should be granted the right to become upstanding citizens and productive members of their community, but disenfranchisement tells them and the people around them that they are not. Removing the stigma is the first step to rehabilitating felons and reducing the rate of reoffenders.
You can read more info here: https://www.sentencingproject.org/publications/felony-disenfranchisement-laws-in-the-united-states/