To support Trump’s claim that “full compliance with the agreement could ultimately shrink America’s GDP by $2.5 trillion over a 10-year period,” Cheung, the White House spokesman, pointed us to a March commentary piece on the Heritage Foundation’s website. That referred to work originally done by Heritage Foundation senior statistician Kevin D. Dayaratna and others in an April 2016 report. The Heritage Foundation’s mission is to “formulate and promote conservative public policies.”

3 billion is just the down payment.