A press conference outside the U.S. Capitol by politicians, legal experts and leaders of environmental groups precedes a hearing by Rep. Lamar Smith (R-Texas), chairman of the House Committee on Science, Space and Technology, on his authority to issue and enforce subpoenas on non-governmental organizations and attorneys general of two states. Smith issued subpoenas seeking emails between non-governmental organizations and attorney generals about investigations about Exxon Mobil's decades long campaign to mislead the public about climate change. Exxon's scientists knew about the connection between the use of fossil fuels and climate change while the company pursued policies designed to cast suspicion on the problem.