For the throngs of schoolchildren who visited the National Constitution Center on Monday, the 225th anniversary of the nation's founding legal document, it might come as a shock that even today millions of Americans are denied the fundamental right to vote.

Even more of a jolt would be the fact that, according to a new study, more than four million of these citizens "live, work, and pay taxes in their communities."

For these individuals - including the one million African Americans who represent a disproportionate share - their voting rights are revoked due to a felony conviction. And their total numbers have seen a troubling, five-fold increase to 5.85 million over the last few decades, according to the Sentencing Project, a national criminal-justice reform group.

While that growth is in line with the nation's increased incarceration rates, it's also due to the spread of misguided state laws that revoke former inmates' franchise long after they supposedly have paid their debts to society.

At least in Pennsylvania, convicts who are barred from voting while in prison are free to vote when they get out. New Jersey and Delaware lawmakers take the harder line, though, barring voting by inmates as well as many parolees.

In some states, there is no path to restore this basic right of citizenship. Others allow former inmates to vote after a period of years.

Yet the reform group notes that a "significant majority" of Americans favor opening the polls to probationers, parolees, and felons who have served their time. The status quo should be even more unacceptable to most citizens, inasmuch as the voting bans weigh unfairly on the nation's minority communities. In particular, 1 of every 13 voting-age African Americans can't vote.

Beyond barring felons from voting as a punitive measure, there's no civic rationale for denying them their political voice. On the contrary, the nation's disenfranchisement laws should be eased as a way to encourage more ex-offenders to be good citizens and get their lives fully back on track.