Updated

A federal appeals court struck down Texas' voter ID law on Wednesday in a victory for the Obama administration, which had taken the unusual step of bringing the weight of the U.S. Justice Department to fight new Republican-backed mandates at the ballot box.

The 5th U.S. Circuit Court of Appeals ruled that the 2011 law carries a "discriminatory effect" and violates one of the remaining provisions of the Voting Rights Act -- the heart of which was struck down by the U.S. Supreme Court in 2013.

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

Section 2 of the landmark civil rights law required opponents to meet a far higher threshold and prove that Texas intentionally discriminated against minority voters.

"We conclude that the district court did not reversibly err in determining that SB 14 violates Section 2 by disparately impacting minority voters," the court wrote.

The Justice Department had argued that the Texas law, considered one of the toughest voter ID measures in the country, would prevent as many as 600,000 voters from casting a ballot because they lacked one of seven forms of approved ID.

“In light of ongoing voter fraud, it is imperative that Texas has a voter ID law that prevents cheating at the ballot box,” Gov. Greg Abbott said in a written statement. “Texas will continue to fight for its voter ID requirement to ensure the integrity of elections in the Lone Star State.”

A lower court had previously found that the voter ID was passed with the intent of discriminating against minorities. In striking down the Texas measure, however, the New Orleans-based appeals court did not find the voter ID requirement to be the equivalent of a poll tax.