A devastating, compelling account of the federal government's leading role in bringing about today's climate crisis. In 2015, a group of twenty-one young people sued the federal government in Juliana v. United States for violating their constitutional rights by promoting climate catastrophe and thereby depriving them of life, liberty, and property without due process and equal protection of law. They Knew offers evidence supporting the children's claims, presenting a devastating and compelling account of the federal government's role in bringing about today's climate crisis. James Gustave Speth, tapped by the plaintiffs as one of twenty-one preeminent experts in their climate case, analyzes how administrations from Carter to Trump—despite having information about the impending climate crisis and the connection to fossil fuels—continued aggressive support of a fossil fuel based energy system.   What did the federal government know and when did it know it? Speth asks, echoing another famous cover-up. What did the federal government actively do and what did it fail to do? They Knew (an updated version of the Expert Report Speth prepared for the lawsuit) presents the most definitive indictment yet of the US government's role in the climate crisis.   Since Juliana v. United States was filed, the federal government has repeatedly taken unprecedented steps to delay the case and force it to the appellate courts' shadow dockets. Yet as the case progresses slowly but certainly, it is inspiring a generation of youthful climate activists.   An Our Children's Trust Book