The decision involves an increasingly contentious political issue in the U.S.: a push, largely by Republican-controlled legislatures and governors, to impose strict identification requirements on voters.

Republicans say they are fighting voter fraud. Democrats, with support from a number of studies, say voter fraud is largely non-existent and that Republicans are trying to disenfranchise minorities, poor people and college students — all groups that tend to support Democrats.

This year’s election is a tight race between President Barack Obama and Republican challenger Mitt Romney.

In the Texas case, the Justice Department called several lawmakers, all of them Democrats, who said they detected a clear racial motive in the push for the voter ID law. Lawyers for Texas argued that the state was simply tightening its laws.

David Tatel, an appeals court judge appointed by President Bill Clinton and writing for the panel, called the Texas law “the most stringent in the nation.” He said it would impose a heavier burden on voters than a similar law in Indiana, previously upheld by the Supreme Court, and one in Georgia, which the Justice Department allowed to take effect without objection.

During an appearance in Texas in July, Attorney General Eric Holder said the state’s photo ID requirement amounts to a poll tax, a term that harkens back to the days after the Civil War when blacks across the South were stripped of their right to vote.

The decision comes the same week that South Carolina’s strict photo ID law is on trial in front of another three-judge panel in the same federal courthouse. A ruling is expected before the November election.

South Carolina’s voter ID requirement became the first such law to be rejected by the Justice Department in nearly 20 years. Romney said the attorney general made a “very serious error” by blocking it.

“We don’t want people voting multiple times,” Romney said.

Last year, new voter ID laws passed in Kansas, Mississippi, Rhode Island and Wisconsin. In addition to Texas and South Carolina, Alabama and Tennessee tightened existing voter ID laws to require photo ID. Governors in Minnesota, Missouri, Montana, New Hampshire and North Carolina vetoed strict new photo ID laws.

A report by the non-governmental Brennan Center for Justice determined that new voting restrictions could suppress the votes of more than 5 million young, minority, low-income and disabled voters.

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Associated Press writer Mark Sherman contributed to this report.