Roger Stone, a former Trump adviser and longtime confidant, panned Steve Bannon on Thursday, saying that President Trump, not Bannon, who has always been the "political genius" behind his insurgent political movement.

He weighed in on Fox News as Trump and Bannon have been cast into a feud over excerpts from an upcoming tell-all book about Trump's first year in office.

"The Trump platform was well settled on long before Steve Bannon joined the campaign," Stone told host Tucker Carlson. "And it appears that [White House policy adviser] Stephen Miller helped the president articulate it. But the agenda is Trump, the drive to win is Trump. The populist campaign is all Donald Trump. Just taking the title of chief strategist is a misnomer, at best."

During the later months of the 2016 presidential contest, Bannon was brought in as the Trump's campaign chief executive officer. Bannon then served as Trump's chief strategist until August when he was let go and returned to Breitbart News as executive chairman.

The White House has distanced itself from Bannon this week after excerpts from a forthcoming book, "Fire and Fury: Inside the Trump White House," by Michael Wolff, were published. The excerpts feature unfavorable comments by Bannon about Trump’s family — remarks Stone called "a stunning act of betrayal."

One excerpt quotes Bannon saying the 2016 Trump Tower meeting between Trump campaign officials, Donald Trump Jr., and a Russian lawyer "treasonous." The meeting has been a subject of interest for investigations into Russian interference in the 2016 campaign and possible collusion between the Trump camp and the Kremlin.

Stone argued that the meeting was "not treasonous, it was not illegal, it wasn't improper," adding that Bannon is "is neither a lawyer nor an experienced political strategist."

"That meeting is a nothingburger," Stone added.