A state appeals court in Baton Rouge is being asked to reconsider the constitutionality of a more than four-decade-old Louisiana law that prohibits felons on probation and parole from voting.

State District Judge Tim Kelley, of Baton Rouge, upheld the 1976 law in March of last year, saying he agreed with the plaintiffs who challenged its legality but could not bend the law.

The plaintiffs — a group called Voice of the Experienced, or VOTE, and several felons — say the law prevents more than 70,000 felons on probation and parole in Louisiana from voting.

The 1st Circuit Court of Appeal affirmed Kelley's ruling last month in a written opinion. The plaintiffs are now asking the court for a rehearing.

"The Opinion results in a grave impact on the fundamental right to vote of thousands of Louisiana's citizens who are on parole and/or probation," attorneys for VOTE and the other plaintiffs argue in their rehearing application filed April 27.

The plaintiffs have vowed to take the case to the state Supreme Court.

The 1974 Louisiana constitution prevents people "under an order of imprisonment" for a felony conviction from voting. A 1976 state law expanded the definition of that phrase, saying felons on probation and parole cannot vote.

The plaintiffs' attorneys argue that "under an order of imprisonment" means a person is actually in prison. The state's lawyers say felons on probation or parole remain under such an order because they can be sent back to prison if they violate the terms or conditions of their probation or parole.

Circuit Judge Toni Higginbotham wrote last month for the 1st Circuit that the fact that a convicted felon is not in prison is irrelevant.

"Convicted felons on parole and/or probation are still in a 'custodial' setting under an order of imprisonment, as they are still serving a portion of a criminal sentence," she reasoned.

Higginbotham agreed that the state has a compelling interest in protecting the integrity of voter registration rolls and in regulating felons still under the state's supervision. She also noted that the U.S. Supreme Court "has long held that convicted felons may be excluded from the right to vote."

The American Probation and Parole Association, and 17 professors from the law schools at LSU, Southern and Tulane universities and Loyola University New Orleans had filed documents at the 1st Circuit supporting the plaintiffs.

Follow Joe Gyan Jr. on Twitter, @JoeGyanJr.