President Obama on Wednesday encouraged Congress to restore a key piece of the Voting Rights Act – requiring states to receive federal approval before changing election laws – following an unfavorable Supreme Court decision from 2013.

"Congress must restore the Voting Rights Act. Our state leaders and legislatures must make it easier – not harder – for more Americans to have their voices heard. Above all, we must exercise our right as citizens to vote; for the truth is that too often we disenfranchise ourselves," Obama wrote in a letter to the editor published in The New York Times.

Obama said he was inspired by a recent New York Times piece that detailed 50 years of opponents' efforts to "undermine this historic law."

"These efforts are not a sign that we have moved past the shameful history that led to the Voting Rights Act. Too often, they are rooted in that history," the president wrote. "They remind us that progress does not come easy, but that it must be vigorously defended and built upon for ourselves and future generations."

A 2013 Supreme Court decision struck down and invalidated a part of the law that required states to receive federal approval before changing election laws. Since then, a number of states governed by Republicans, including North Carolina and Texas, have passed laws that restrict early voting, require voters to provide identification at the polls and ban pre-registration for people under 18, explains The Hill.

Obama specifically mentioned 94-year-old Rosanell Eaton, a plaintiff in the ongoing North Carolina case against some of those voting restrictions, which Eaton says was designed to discriminate against black voters, according to Politico.

"I am where I am today only because men and women like Rosanell Eaton refused to accept anything less than a full measure of equality. Their efforts made our country a better place. It is now up to us to continue those efforts," Obama wrote.