Steve Bannon, President Donald Trump's former chief strategist, called the firing of FBI director James Comey potentially the biggest mistake in “modern political history”. Speaking to CBS News' Charlie Rose in a “60 Minutes” interview Bannon also said he believed the current investigation conducted by special counsel Robert Mueller would not be taking place if Comey had not been fired. Mueller is leading the investigation into the possible Russian interference in the 2016 U.S. presidential election.