Pro to the question "Should Felons Who Have Completed Their Sentence (Incarceration, Probation, and Parole) Be Allowed to Vote?"
"Americans may see it as common sense that you lose your right to vote when you're imprisoned, but in many democracies prisoners retain the right to vote. When that right is revoked, it's only for particular crimes (in Germany, it's for 'targeting' the 'democratic order'), and often there is a good deal of judicial discretion. Mandatory disenfranchisement is unusual, and permanent disenfranchisement is even rarer...
Prisoners are neither more nor less rational than anyone else who is allowed to vote.
If anything, the political system needs the perspectives of prisoners, with their intimate experience of this otherwise opaque part of the state. Their votes might force lawmakers to take a closer look at what happens in these institutions before they spiral into unaccountable violence and abuse.
There are practical benefits as well. Racial disparities in criminal enforcement and sentencing means disenfranchisement falls heaviest on black communities. This is not just a direct blow to prisoners' electoral power; it also ripples outward, depressing political participation among their friends, families and acquaintances. On the other end, suffrage in prison may help incarcerated people maintain valuable links to their communities, which might smooth the transition process once they're released."
Jamelle Bouie, "Tell Me Again Why Prisoners Can't Vote," nytimes.com, Apr. 11, 2019