The Supreme Court gave the Trump administration another immigration win on Wednesday, blocking a federal injunction that would have halted the Migrant Protection Protocols (MPP) — or "Remain in Mexico" policy — in California and Arizona.

Why it matters: The Trump administration sent military troops to parts of the border ahead of the decision in order to prepare for any surges of migrants crossing the border if MPP was halted, per the New York Times.

The big picture: The policy has kept tens of thousands of asylum-seekers on Mexican soil to wait out their immigration court hearings. The program has been credited for helping lower the border crossing numbers from crisis levels.

Last month, the 9th Circuit Court of Appeals upheld a lower court's injunction — halting the program — only for it to reverse course a couple of hours later.

The back and forth comes ahead of a season where border crossings typically start to climb to their peak for the year.

Between the lines: The Supreme Court has yet to rule on the legality of the MPP program itself. This order simply allows the program to continue while lawsuits make their way through the federal court system.

What they're saying:

"We are gratified that the Supreme Court granted a stay, which prevents a district court injunction from impairing the security of our borders and the integrity of our immigration system. The Migrant Protection Protocols, implemented pursuant to express authority granted by Congress decades ago, have been critical to restoring the government’s ability to manage the Southwest border and to work cooperatively with the Mexican government to address illegal immigration."

— DOJ spokesperson

“The Court of Appeals unequivocally declared this policy to be illegal. The Supreme Court should as well. Asylum seekers face grave danger and irreversible harm every day this depraved policy remains in effect.”

— Judy Rabinovitz, special counsel in the ACLU’s Immigrants’ Rights Project