The Supreme Court will decide cases this term on two of the Trump administration’s most contentious U.S.-Mexico border policies: transferring $2.5 billion in Defense Department funds to build a border wall and keeping immigrants who illegally cross that border in Mexico while their removal proceedings are pending.

On both issues, the justices have already weighed in on the side of the Trump administration. The Supreme Court allowed the government to use funds to build the barrier as the lawsuits go through the court system, as well as implement the “remain in Mexico” policy while it is being challenged.

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But both issues brought to the court by the Trump administration could be wiped out before the Supreme Court ever decides them. If Democrat Joe Biden becomes president in January, he is expected to undo many of President Donald Trump’s immigration policies.

In the border wall case, the justices agreed to decide whether the Sierra Club has the legal right to challenge the transfer of the funds in court, and if so, whether the then-acting Defense secretary exceeded the administration’s authority under a fiscal 2019 appropriations law.

The House also filed a lawsuit in Washington to stop the border wall spending. That case is still being litigated.

The Trump administration asked the Supreme Court to hear the case after a federal district court judge in California ordered the Defense Department to halt the border construction project.

The U.S. Court of Appeals for the 9th Circuit backed that district court decision in June, finding that the transfer violated the Appropriations Clause of the Constitution, which “exclusively grants the power of the purse to Congress.”

The 9th Circuit found that the border wall did not fit under Section 8005 of the appropriations law, which allows some transfers without congressional authorization, because the project was not an unforeseen military requirement and Congress had denied funding for the wall.

But the Supreme Court, on a 5-4 vote in July 2019, already had allowed the Trump administration to move forward with spending the transferred funds as the challenge went through the court system.

At that time, the court’s majority wrote that among the reasons for allowing the construction is that the environmental groups had no right to file a lawsuit to get a court to review whether the Defense Department was complying with Section 8005 of the law.

One year later, in July, the Supreme Court on a 5-4 vote also denied a new request from the environmental groups to halt construction while the appeal is at the high court. The groups argued that the government would be able to complete the contested projects before the justices decided the case.

An attorney for the American Civil Liberties Union, which brought the lawsuit on behalf of the Sierra Club and the Southern Border Communities Coalition, said the court can put an end to the “unconstitutional power grab.”

“Everyone knows that Trump failed to get Congress to fund his xenophobic wall obsession, and every lower court that has considered the case has found that the President has no authority to waste billions of taxpayer dollars on construction,” Dror Ladin, a senior staff attorney with the ACLU’s National Security Project, said in a news release.

The Supreme Court also announced Monday that it will decide whether the Trump administration can implement a 2018 policy known as Migrant Protection Protocols, which forces migrants to wait out their U.S. court cases in Mexico, often in dangerous border communities.

A federal district judge in California ordered the program stopped in April 2019, and the 9th Circuit in February 2020 found that the policy likely violates federal immigration law and halted implementation for the border states of California and Arizona.

But the Supreme Court in March allowed the Trump administration to continue the policy, which the government told the justices had been applied to more than 60,000 immigrants who would otherwise have needed to be detained in the United States or released into the country.

Court hearings have been suspended for months due to the coronavirus pandemic, so MPP migrants are not actually able to go to court anymore.

The court is expected to decide the cases by the conclusion of the term at the end of June.