A federal appeals court struck down Texas’s voter-identification law Wednesday in a victory for President Obama, whose administration took the unusual step of bringing the weight of the Justice Department to fight a wave of new ballot-box restrictions passed in conservative statehouses.

The U.S. Court of Appeals for the 5th Circuit in New Orleans ruled that the 2011 Texas law carries a “discriminatory effect” and violates the federal Voting Rights Act — handing down the decision on the eve of the 50th anniversary of the landmark civil rights law.

Texas was allowed to use the voter-ID law during the 2014 elections, thereby requiring an estimated 13.6 million registered voters to have a photo ID to cast a ballot.

The ruling was a victory, although not a sweeping one, for Democrats and minority rights groups. Last year, a Texas federal judge called the law the equivalent of a poll tax, but the three-judge panel of the New Orleans court disagreed. Instead, it sent the law back to the lower court to consider how to fix the discriminatory effects. Texas can appeal the unanimous decision to the full appeals court, or ask for a Supreme Court review.

Until then, Texas Attorney General Ken Paxton (R) said the law will remain in effect, although he did not acknowledge the issues raised by the court’s mixed ruling.

“I’m particularly pleased the panel saw through and rejected the plaintiffs’ claim that our law constituted a ‘poll tax,’ ” Paxton said. “The intent of this law is to protect the voting process in Texas, and we will continue to defend this important safeguard for all Texas voters.”

Other Republican-controlled states, including Wisconsin and North Carolina, have passed similar voter-ID measures in recent years, but the Texas law signed by then-Gov. Rick Perry is widely viewed as one of the nation’s toughest. It requires one of seven forms of approved identification, a list that included concealed carry licenses but not a college student’s university ID.

“Today’s ruling is a victory for every Texas voter,” Texas Democratic Party Chairman Gilberto Hinojosa said. “Once again, the rule of law agrees with Democrats. The Republican voter-ID law is discriminatory.”

Gov. Greg Abbott (R) called it “imperative” that Texas has a voter-ID law and said the state will continue fighting for the measure.

Democrats and minority rights advocates had early success in blocking the law. But after the Supreme Court struck down the heart of the Voting Rights Act in 2013, the path was cleared for Texas to enforce the new restrictions that supporters say prevent voter fraud.

Section 5, one of the parts of the act that were struck down, had forced certain state and local governments — including Texas — to get pre-clearance from the federal government before changing voting laws, to ensure they were free of discrimination.