two republican former environmental protection agency chiefs warn trump presidency would set world back decades could also direct threat environmental legacies presidents ronald reagan richard nixon george h.w bush result decide back hillary clinton rather republican nominee.william d. ruckelshaus william k. reilly issue statement tuesday announce endorsement clinton.republicans long history support environment date back theodore roosevelt donald trump threaten destroy legacy respect environment protection public health statement read.ruckelshaus epa administrator reagan nixon reilly serve bush praise environmental policies administrations work say trump slight clue donald trump show profound ignorance science public health issue embody environmental laws say clue republicans historic contributions science-driven environmental policy former epa head also slam trump claim climate change call singular health environmental threat world today nothing hoax fly face overwhelm international science public conviction commitment almost 200 national governments adopt paris agreement climate change december 2015 say point leadership essential agreement back away trump want would set world back decades years could never recover young people country deserve far good legacy addedthey write clinton hand acknowledge climate change threat concern protect environment commit reasonable science-based policy meet challenge men write us simply choice election conclude republicans shock outrage even prospect progress legacy repudiate roll back donald trump hugely consequential election stake high republicans support hillary clinton president feature image via joe raedle/getty image former gop epa chiefs endorse clinton trump would set world back decades