Next Tuesday, tens of millions of Americans will take to the polls to vote on everything from ballot issues to federal, state and local representation. But millions of voting-age adults will be sitting this one out.

An estimated 5.85 million Americans won’t be able to vote due to prior felony convictions, according to an estimate from the Sentencing Project, a criminal justice nonprofit think tank. Of those, roughly 44 percent are estimated to be felons who live in the 12 states that still restrict voting rights after sentences have been served, a practice that excludes as many as 1 in 10 voting-age residents of Florida, the state with the highest rates of felon disenfranchisement.

The disproportionate effect on blacks

Such policies have a disproportionate impact on blacks, restricting the vote for roughly 1 in 13 voting-age blacks nationwide.

But in some states, the rate is much higher. More than 20 percent of voting-age blacks in Florida, Kentucky and Virginia will not be able to vote due to felony convictions—whether or not they have fully served their sentences. In six more states, such policies affect between 10 percent and 20 percent of black adults.

Overall disenfranchisement rates by state

Florida is home not only to the highest rates of black felon disenfranchisement, but overall disenfranchisement, too. More than 10 percent of voting-age Floridians are not able to vote. Mississippi is next, with a disenfranchisement rate of 8.3 percent. Another five states—Kentucky, Virginia, Alabama, Tennessee, and Wyoming—have rates above 5 percent.

Impact on the election

Felon voting restrictions could have consequences on the election, especially where races are tight, such as the battleground states highlighted by the Sentencing Project graphic above.

A policy rooted in post-Reconstruction America

The Sentencing Project’s estimates for disenfranchisement in the current election are based off of a 2012 report and are in line with numbers cited by Attorney General Eric Holder, who in February made the case for restoring voting rights for felons.

In that speech, Holder said that such laws were used by states after the Civil War to keep blacks from casting ballots. Blacks account for 38 percent of disenfranchised Americans. Such disenfranchisement rates are highest in the South, as the proportional 2010 map below shows.

Who has the strictest felon-voting restrictions?

Only two states—Maine and Vermont—allow felons in or out of prison to vote. Thirteen states and D.C. prohibit voting for those currently in prison or jail. Four more states also ban voting for those on parole. Nineteen states ban voting for this in prison or jail, out on parole or out on probation. And 12 states additionally ban voting in at least some way for voting-age adults who have fully served their sentence.