The Trump administration in two weeks might face something it’s tried for months to avoid: a courtroom battle over its failure to address climate change.

A novel climate constitutional case brought by a group of mostly teenagers should advance to trial, a federal district court judge in Oregon said in an Oct. 15 opinion.

The court order largely denied several motions from the Justice Department that have accumulated over months seeking to resolve or wholly kill the lawsuit before its trial date of Oct. 29.

If the case succeeds, it could force the government to develop a comprehensive policy to...