The US Supreme Court has made it easier for states to enact voting restrictions, endorsing Republican-backed measures in Arizona that a lower court had said disproportionately burdened minority voters.
The 6-3 ruling held that the restrictions on early ballot collection by third parties and where absentee ballots may be cast did not violate the Voting Rights Act, a landmark 1965 federal law that prohibits racial discrimination in voting.
The court's three progressive justices dissented from the decision, which was authored by conservative Justice Samuel Alito.
The decision comes at a time when states are enacting a series of Republican-backed voting restrictions following former president Donald Trump's allegations of widespread election fraud in his 2020 loss to now-President Joe Biden.
The ruling represented a victory for the Arizona Republican Party and the state's Republican attorney general, Mark Brnovich.
They had appealed a ruling by the San Francisco-based 9th US Circuit Court of Appeals that had deemed the restrictions unlawful.
The decision was issued on the last day of rulings for the court's current nine-month term.
The Arizona ruling clarified the limits of the Voting Rights Act and how courts may analyse claims of voting discrimination.
The "mere fact there is some disparity in impact does not necessarily mean that a system is not equally open or that it does not give everyone an equal opportunity to vote," Alito said.
In a scathing dissent, liberal Justice Elena Kagan called the ruling "tragic," noting that it comes as states are erecting new barriers to voting, even banning the handout of water to voters standing in line.
"So the court decides this Voting Rights Act case at a perilous moment for the nation's commitment to equal citizenship. It decides this case in an era of voting-rights retrenchment - when too many states and localities are restricting access to voting in ways that will predictably deprive members of minority groups of equal access to the ballot box," Kagan wrote.
The case involves a 2016 Arizona law that made it a crime to provide another person's completed early ballot to election officials, with the exception of family members or caregivers.
Community activists sometimes engage in ballot collection to facilitate voting and increase voter turnout.
Ballot collection is legal in most states, with varying limitations.
Republican critics call the practise "ballot harvesting".
The other restriction at issue was a longstanding Arizona policy that discards ballots cast in-person at a precinct other than the one to which a voter has been assigned.
In some places, voters' precincts are not the closest one to their home.
In Thursday's ruling, Alito endorsed a state's right to enact restrictions to combat fraud.
"One strong and entirely legitimate state interest is the prevention of fraud. Fraud can affect the outcome of a close election" and can undermine public confidence in elections, Alito said.
Democrats have accused Republicans at the state level of enacting voter-suppression measures to make it harder for racial minorities who tend to support Democratic candidates to cast ballots.
Many Republicans have justified new restrictions as a means to reduce voter fraud.
"Today is a win for election integrity safeguards in Arizona and across the country," Brnovich said.
Arizona Republicans have argued that "race-neutral" regulations on the time, place or manner of an election do not deny anyone their right to vote and that federal law does not require protocols to maximise the participation of racial minorities.