President Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE's former economic adviser Gary Cohn Gary David CohnGary Cohn: 'I haven't made up my mind' on vote for president in November Kushner says 'Alice in Wonderland' describes Trump presidency: Woodward book Former national economic council director: I agree with 50 percent of House Democrats' HEROES Act MORE took aim at Trump's trade adviser Peter Navarro on Wednesday by referring to Navarro as the only Ph.D-holding economist in the world who believes in the effectiveness of tariffs.

In an interview with the "Freakonomics" podcast, Cohn remarked that "99.99999" percent of top economists agreed with his assertion that "tariffs don't work."

"If anything, they hurt the economy because if you're a typical American worker, you have a finite amount of income to spend," he continued.

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"Now, every Ph.D. economist that I've ever come across would agree — I would say, probably 99.5 percent — with what you just said," responded the host, Stephen Dubner.

"But the one that doesn't, is in the White House, which is Peter Navarro, is that right?" Dubner added.

"There's only one in the world. That we know of," Cohn responded.

Cohn went on to lament his inability to convince Trump not to implement tariffs on countries such as China as well as top U.S. allies such as Canada, Mexico and the European Union.

"I was losing the war on tariffs every day with the president. I knew I wasn't convincing him I was right. I was not going to take a 74-year-old man who's believed something since he was 30 and convince him that I was right. Believe me, I tried. It — don't think I didn't try," Cohn said.

Cohn left the National Economic Council last year after clashing with the president on issues of trade as well as Trump's response to riots in Charlottesville, Va., which were started by white nationalists and left one person dead.

He has since told reporters he has felt "freer" and "happier" since leaving the White House, while maintaining his opposition to the president's tariff policies.

“No one wins in a trade war,” Cohn said last year. “What we do need in America, and I think what everyone does believe in … is free, fair, open and reciprocal.”

“In a perfect world, we would have no tariffs,” he added.