The order also permitted three fossil fuel industry trade associations, who had voluntarily joined the case last year as intervening defendants, to withdraw at their own request. This means the final showdown will take place only between the original plaintiffs and defendants  21 youths, between ages 9 and 21, and the federal government, which they claim has violated their constitutional right to a healthy climate system by supporting the production of fossil fuels and emission of greenhouse gases. While originally filed against the Obama administration, the Trump administration has now assumed the defense by default.