Attorney General Eric Holder said the Justice Department will go to court to force Texas to get permission from the federal government before it can change its voting laws.
Holder called the Voting Rights Act "the cornerstone of modern civil rights law."
"We cannot allow the slow unraveling of the progress that so many, throughout history, have sacrificed so much to achieve," he said.
The U.S. Supreme Court ruled 5-4 in June that requiring certain southern states to get the agency's approval before changing their election laws is outdated.
Texas Gov. Rick Perry fired back at Holder, accusing the Obama administration of making an end-run around the high court.
"Once again, the Obama administration is demonstrating utter contempt for our country's system of checks and balances, not to mention the U.S. Constitution," Perry said in a statement.
"This end-run around the Supreme Court undermines the will of the people of Texas, and casts unfair aspersions on our state's common-sense efforts to preserve the integrity of our elections process," he charged.