WASHINGTON — The Supreme Court on Friday refused to halt the trial in a lawsuit brought by 21 young people seeking to force the federal government to take action to address climate change.

The court’s unsigned order said the Trump administration had raised substantial questions about the plaintiffs’ legal theories and the sweeping relief they sought. But the court said it would not intercede, instructing the plaintiffs to take the case back to an appeals court.

Julia Olson, the lead lawyer for the plaintiffs, said in a statement, “The youth of our nation won an important decision today from the Supreme Court that shows even the most powerful government in the world must follow the rules and process of litigation in our democracy.”

Justices Clarence Thomas and Neil M. Gorsuch said they would have granted the administration’s request to block the trial until the Supreme Court had an opportunity to consider the case.