PORTLAND, Ore. (AP) — In a courtroom packed with environmental activists, federal judges wrestled Tuesday over whether climate change violates the rights of young people who have sued the U.S. government over the use of fossil fuels.

A U.S. Justice Department lawyer said the young people wrongly want the courts to direct energy policy, instead of government officials. Jeffrey Clark, an assistant attorney general, told three judges from the 9th U.S. Circuit Court of Appeals that the lawsuit is "a direct attack on the separation of powers."

An attorney for the young people countered that governm...