The Supreme Court did not offer a reason for its decision, but three justices dissented. (Jonathan Ernst/Reuters)

The Supreme Court’s order that Texas can proceed with its strict voter-ID law in next month’s election ended what is likely to be just the first round in a legal battle over election-law changes made by Republican-led legislatures around the country.

In an order released just after 5 a.m. Saturday, the court said Texas could use a photo-ID law that has been described as the toughest in the nation. A district judge had declared after hearing testimony about the law that it was unconstitutional, and would keep hundreds of thousands of voters from casting ballots and disproportionately harm African Americans and Hispanics.

The Supreme Court’s unsigned order did not address the merits of the law, nor did it supply reasoning for the decision to allow it to be enforced.

The court has been called upon to make emergency decisions about laws in four states, including Texas, in recent weeks, and in each case has decided against intervening in a state’s plan for conducting elections so close to the start of voting.

In the Texas case, it was impossible to discern how each justice voted, although Justice Ruth Bader Ginsburg issued a stern dissent, which was joined by Justices Sonia Sotomayor and Elena Kagan.

Ginsburg leaned heavily on the findings of U.S. District Judge Nelva Gonzales Ramos, and said both the appeals court and her colleagues should have deferred to the trial judge rather than allow a potentially unconstitutional law to be used simply because the election is at hand. Early voting in Texas begins Monday.

“The greatest threat to public confidence in elections . . . is the prospect of enforcing a purposefully discriminatory law, one that likely imposes an unconstitutional poll tax and risks denying the right to vote to hundreds of thousands of eligible voters,” Ginsburg wrote.

She said a panel of the U.S. Court of Appeals for the 5th Circuit had shirked its duty, since Ramos had agreed with the challengers that the law could keep an estimated 600,000 registered voters from casting ballots. Texas disputes the finding.

U.S. Attorney General Eric H. Holder Jr., who had challenged the law, called the order a “major step backward.”

“It is true we are close to an election, but the outcome here that would be least confusing to voters is the one that allowed the most people to vote lawfully,” Holder said in a statement.

Officials in Texas said they were pleased by the court’s decision.

“The state will continue to defend the voter ID law and remains confident that the district court’s misguided ruling will be overturned on the merits,” said a statement from Lauren Bean, deputy communications director for Texas Attorney General Greg Abbott, who is also the Republican candidate for governor. “The U.S. Supreme Court has already ruled that voter ID laws are a legal and sensible way to protect the integrity of elections.”

The Texas law, called SB 14, requires the state’s estimated 13.6 million registered voters to show one of seven kinds of photo identification to cast a ballot.

The state says the law will guard against voter fraud and protect public confidence in elections. But civil rights groups and the Justice Department said the state’s decisions about what kinds of identification will suffice — permits to carry concealed handguns qualify, for instance, while college IDs do not — are meant to suppress certain types of voters.

Ramos agreed with the challengers that black and Hispanic voters are more likely to lack the specific kinds of identification that Texas requires and would have more trouble than white voters in securing them.

Ginsburg noted that those without proper ID may obtain an “election identification certificate” from the Texas Department of Public Safety, but more than 400,000 eligible voters face round-trip travel times of three hours or more to the nearest office.

For those and other reasons, the Texas law originally was blocked under Section 5 of the federal Voting Rights Act, which required states and localities with a history of discrimination to have election-law changes precleared by federal authorities.

But after the Supreme Court in 2013 effectively struck down that requirement, Texas began using the law in nonfederal elections and told the court that it has been implemented in state elections without the dire consequences the challengers predicted.

Texas said the Supreme Court in 2008 validated the use of photo IDs in a case involving an Indiana law. And in his filing with the court, Abbott denied that the state’s solidly Republican leadership had ulterior motives.

“The legislature enacted SB 14 because voter identification laws are popular (as evidenced by their enactment in numerous states) and because they have been specifically approved by this court as a means to deter and detect fraud and improve public confidence in the election process,” Abbott wrote.

“A legislature is not racist for enacting a voting requirement that the Supreme Court has found to serve legitimate state interests — even if that requirement is alleged to have a disparate impact on racial minorities.”

In the past few weeks, the court has ruled on a number of emergency challenges to election laws rewritten by state legislatures and scheduled to be implemented in next month’s voting.

The court allowed Ohio to reduce the number of days early voting is offered and agreed that North Carolina could end same-day voter registration. But it blocked a new voter-ID law in Wisconsin, where early voting had already begun.

None of the decisions addressed the merits of the laws, although each will continue to be challenged, and it is likely that some will return to the Supreme Court.