Why Did Steve Bannon Say That Trump's Decision To Fire Comey Was A Terrible Mistake?

Steve Bannon was interviewed by Charlie Rose on 60 Minutes.  One of Bannon's comments, that did not make the final cut to the TV show,  is discussed in this article.  Bannon believes that Trump's decision to fire James Comey was one of the biggest political mistakes in modern history.  What did Bannon mean by that statement?  Bannon had already stated that was not aware of any collusion between between the Trump campaign and Russia. Therefore, he must believe that Trump might have set the stage for an obstruction of justice charge, or "something else".  Since the firing of James Comey led to the appointment of a Special Counsel, Bannon may be concerned about the "something else" issue.

The fact that the Special Counsel is looking broadly into the case suggests that digging into Trump's financial history will uncover incriminating financial dealings that could bring down his administration.  Bannon probably understands why Trump refused to release his tax returns and he is aware of Trump's dependency on foreign lending arrangements which might make him susceptible to blackmail and other forms of foreign influence.