Friday's firing of FBI Deputy Director Andrew McCabe by Attorney General Jeff Sessions, based on a report from the Office of Professional Responsibility, is only the beginning of what is likely to be the most explosive series of revelations in American history. Forget Watergate. It will be the distant past once the Inspector General's reports—there apparently will be more than one—start to come out. This will be the "Gate of Gates." From the FBI and across the intelligence agencies an astonishing number of people are going to find themselves accused, one can safely predict at this point, of some atrocious...