Story highlights Small non-profit played a major role in Trump's climate agreement decision

Myron Ebell served as the head of Trump's EPA transition team

Washington (CNN) Myron Ebell hadn't met President Donald Trump until Thursday at the White House following the President's decision to pull out of the Paris climate accord.

But Ebell, the head of Trump's Environmental Protection Agency transition team, likely had as much influence shaping Trump's decision as any single individual.

As director of the Competitive Enterprise Institute, a non-profit policy center that was in favor of withdrawing from the Paris agreement, Ebell had direct and indirect influence that might have helped change the political and environmental direction of the US.

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Following news that Trump was waffling on whether or not to uphold his campaign promise of withdrawing the US from the pact, Ebell's CEI put out a TV ad with video montages of Trump promising to do just that during the election.

Speaking to CNN, Ebell said the point was to remind the President what promises he had made to his voters -- and Ebell believes it worked.