Montana's Landmark Climate Lawsuit: Final Arguments and Defense Begin.

Montana officials downplayed a first-of-its-kind climate lawsuit brought by 16 young plaintiffs who are asking a judge to declare unconstitutional a state law that prevents agencies from considering the impacts of greenhouse gases when issuing permits for fossil fuel development. The state's lead environmental regulator said permitting practices would not change if the young environmentalists win their case. Final arguments were expected Tuesday, days earlier than scheduled after the state did not call one expert witness who was expected to testify and sharply limited the testimony of a second expert.