Even before Donald Trump chooses a Supreme Court nominee, the new president can take steps to make several contentious court cases go away.

Legal challenges involving immigration, climate change, cost-free contraceptive care and transgender rights all could be affected, without any help from Congress.

The cases turn on Obama administration policies that rely on the president’s pen, regulations or decisions made by federal agencies. And what one administration can do, the next can undo.

It is not uncommon for the court’s docket to change when one party replaces the other in the White House. That change in direction is magnified by the high-court seat Trump will get to fill after Senate Republicans refused to consider President Barack Obama’s nomination of Judge Merrick Garland.

“We were hoping we’d be looking forward to a progressive majority on the Supreme Court. After the election results, there is a new reality,” said Elizabeth Wydra, president of the liberal Constitutional Accountability Center.

The Supreme Court already is set to consider a case involving a transgender teen who was born female, but identifies as a male and wants to use the boys’ bathroom at his Virginia high school. When the federal appeals court in Richmond ruled in student Gavin Grimm’s favor this year, it relied on a determination by the U.S. Education Department that federal law prohibiting sex discrimination in education also applies to gender identity.

The new administration could withdraw the department’s guidance, which could cause the justices to return the case to the lower courts to reach their own decision about whether the law requires schools to allow students to use bathrooms and locker rooms based on their gender identity.