When asked if the firing of former FBI Director Comey "was the biggest mistake in modern political history," Bannon told CBS News' "60 Minutes" that he would "leave it at that."
"I don't think there's any doubt that if James Comey had not been fired, we would not have a special counsel, yes," Bannon said in the interview that aired Sunday.
Bannon said the ongoing investigation by former FBI Director Robert Mueller would not have begun if Trump had kept Comey as the head of the FBI. Now Mueller is leading a special counsel to investigate Russian interference in the 2016 U.S. presidential election.
"We would not have the Mueller investigation and the breadth that clearly Mr. Mueller is going for," Bannon said.
In the same interview with CBS, Bannon also said top Trump economic advisor Gary Cohn should have resigned after disagreeing with the president's reaction to violent protests in Charlottesville, Virginia.
"Absolutely," Bannon said when asked if Cohn should have stepped down.
"If you don't like what he's doing and you don't agree with it, you have an obligation to resign," Bannon told CBS' "60 Minutes," in a segment of the interview posted Thursday.
Watch the "60 Minutes" interview here.