Slavery was banned by the 13th Amendment to the United States Constitution right?
Well, only sort of. Both the 13th Amendment and Colorado's state constitutional counterpart have exceptions to the prohibition on slavery and involuntary servitude for punishments for crimes. Both the federal and Colorado constitutions allow someone to be declared a slave, or more realistically, subjected to a term of forced labor, as punishment for a crime.
But, in this November's election, the state legislature has decided to ask voters to remove the punishment for a crime exception to the slavery and involuntary servitude clause of the state constitution. Inmates could still volunteer to do prison labor or work on a chain gang because there was some benefit to them in doing it, but they couldn't be forced to do so as part of their crime.
For prison inmates, this makes a lot of sense, but it might be worth some thought to determine how, if at all, this would impact sentences of community service for minor misdemeanor or ordinance violations that don't involve incarceration. My sense is that these sentences are predominantly awarded in plea bargains or at least with defendant consent, and that defendants would consent to this option. But, I'm not certain.