President Donald Trump’s travel ban on six mainly-Muslim countries can go into full effect, pending legal challenges.
The ruling by the US Supreme Court is a boost for Trump’s policy against travellers from Chad, Iran, Libya, Somalia, Syria and Yemen.
The decision covers the third version of the directive that the president has issued since taking office last year.
Seven of the nine justices lifted injunctions on Monday imposed by lower courts against the policy.
Only liberal Justices Ruth Bader Ginsburg and Sonia Sotomayor would have allowed the president’s order to remain blocked.
Federal appeal courts in San Francisco and Richmond, Virginia, will hear arguments this week on whether the latest iteration of the policy is lawful.
The Supreme Court noted it expects those courts to reach decisions “with appropriate dispatch”.
The case will eventually end up back in the Supreme Court, the BBC reported.
The decision suggests the top judicial body in the US may ultimately rule in favour of the administration, say legal analysts.
David Levine, a University of California Hastings law school professor, told the Associated Press: “It suggests that from their understanding, the government is more likely to prevail on the merits than we might have thought.”