The US Supreme Court has granted a Trump administration request to allow the use of a federal database to weed out potential non-citizens from the voter rolls.
A majority of the nine justices on the top court joined the unsigned opinion, providing a victory to President Donald Trump ahead of the November mid-term elections.
The three liberal justices on the conservative-dominated court dissented.
Trump has stated for years that many non-citizens vote in US elections and that mail-in ballots are vulnerable to fraud.
Friday's Supreme Court decision lifted a lower court order that had blocked the use of a Department of Homeland Security program known as Systematic Alien Verification for Entitlements (SAVE) to verify the citizenship of individuals on the voter rolls.
SAVE is used to identify citizenship status to determine whether someone is eligible for benefits.
Ruling against the Trump administration in June, the lower court said, "States have partnered with the federal government to access the database and are actively removing United States citizens from voter rolls based on inaccurate information.
In its ruling, the Supreme Court said the federal government "has an obligation to respond to requests from state and local election officials seeking to verify the citizenship of voters."
The lower court order blocking the use of SAVE "prevents the Federal Government from using the programme it believes is best suited to the task."
“Victory for election integrity”
US Attorney General Todd Blanche welcomed the Supreme Court ruling as a "huge victory for election integrity," saying it will "allow states to clear the voter rolls of illegal voters."
Election experts, however, said the ruling is unlikely to have a major impact on the November elections because most US states ban purges of voters 90 days ahead of an election.
"Both the majority and dissent agree that this case is likely to have limited impact on the midterms," Rick Hasen, a law professor at the University of California, Los Angeles, said in a blog post.
"Compared to the recent mail-in voting case, this one is not very important substantively."
Hasen was referring to a Supreme Court decision earlier this month that blocked a Trump plan that would have restricted the use of mail-in ballots.
Trump reacted furiously to that ruling, calling it "horrible" in a Truth Social post.
