Every state except Maine and Vermont restricts the voting rights of convicted felons. In most cases, felons are prohibited from voting while incarcerated. But ten states bar some felons from ever voting again, and Florida, Iowa, Kentucky and Virginia bar all felons for life unless they receive clemency from the governor. "In Mississippi, passing a $100 bad check carries a lifetime ban from voting."
This is a civil rights issue that has potentially important implications: "Studies show that felons who have been denied the right to vote were far more likely to have voted for Democrats than for Republicans. In 2002, scholars at the University of Minnesota and Northwestern University concluded that the 2000 presidential election “would almost certainly have been reversed” had felons been allowed to vote."
This Pew Charitable Trusts interactive feature (http://www.pewstates.org/research/data-visualizations/states-divided-on-felon-voting-rights-85899541006) shows each state's felon voting policies and voter disenfranchisement.