Do Prisoners have the right to Vote ?

Prisoners do have the right to vote in certain states. I think prisoners should absolutely be allowed to vote if they are mentally fit and are not serving life sentences especially considering that the United States has a higher proportion of its population in prison than any other Western nation and more than Russia or China. It's wrong to marginalize a group of people that large. They are still American citizens with legitimate political and social concerns for themselves and loved ones who are affected by elections.