Valerie Volcovici and P. J. Huffstutter, “Trump Administration Seeks to Muzzle U. S. Agency Employees,” Reuters, Jan. 24, 2017; Lisa Friedman, “E.P.A. Cancels Talk on Climate Change by Agency Scientists,” New York Times, Oct. 22, 2017; Dan Merica and Dana Bash, “Trump Admin Tells National Park Service to Halt Tweets,” CNN Politics, Jan. 23, 2017.