Washington DC - The US Supreme Court ruled on Thursday to allow president Joe Biden to end former president Donald Trump's "Remain in Mexico" policy.

The controversial 2019 policy, which required some unauthorized immigrants, including non-Mexicans and asylum seekers, to be sent to Mexico while their immigration proceedings played out, may soon be shut down.

In a 5-4 vote, the Supreme Court justices ruled in favor of Biden to axe the program.

Conservative justices John Roberts and Brett Kavanaugh surprisingly ruled in Biden's favor, joined by the court's three liberal justices.

Donald Trump Trump reveals new pick for attorney general after Gaetz withdraws

The decision marks a big win for the Biden administration, which sought to end the policy shortly after the president took office. But the attempt was met with opposition from red states, led by Texas and Missouri, who challenged the move in court.

Greg Casar, the current Democratic nominee for the 35th congressional district in Texas, said in a press release the policy "drives immigrants into the shadows" and "turns away vulnerable people."

"The fact that the GOP-packed Supreme Court nearly made the wrong decision on the case shows the need to expand the court, abolish the filibuster, and codify protections for abortion rights, marriage equality, and a pathway to citizenship for immigrant families," Caser added.

Now, immigration officials can release asylum-seekers into the US while they await their visa hearings.