Miller noted that McCabe's main consideration, as McCabe has said in several interviews, was how to make the case "unkillable." That is, neither Deputy Attorney General Rod Rosenstein nor Attorney General Jeff Sessions, nor the next possible attorney general, et al., could "kill this thing without explaining why they killed an investigation into the president himself," explained Miller. "I think once he took that step, it left Rod Rosenstein with no choice but to appoint a special counsel."

Former U.S. Attorney Joyce Vance agreed. "It wasn't at all clear that we would end up with a special counsel," she noted. But rolling the president into existing matters, with a full investigation already in process, "put Rod Rosenstein into a position where, whether he was inclined to do it or not, the only option—because of conflict issues, because of DOJ internal policy—would have been to go with a special counsel."

The context is important here. This was just after Comey had been fired, with the White House touting a memo authored by Rosenstein, and before Rosenstein had perhaps regained some credibility by appointing Robert Mueller to handle the independent investigation. Also, both Sessions and Rosenstein had signed off on Comey's dismissal during a time when Comey was overseeing an investigation into Trump. So from an FBI standpoint, it must have looked like an all-out assault on the rule of law in which Trump, Sessions, and Rosenstein were all potentially complicit.

Additionally, McCabe told Wallace that he immediately believed his days were numbered once Comey was fired because he knew Trump had routinely complained about him to Comey. McCabe also saw what he described as the "rambling" four-page letter in which Trump had initially laid out his reasons for firing Comey. In that letter, Trump listed Comey's failure to fire McCabe as one of his reasons. Remember, that letter was never released to the public; instead, then-White House counsel Don McGahn buried it in a safe and the White House released Rosenstein's memo instead as the basis for Comey’s firing. Nonetheless, McCabe had good reason to believe that his days as acting FBI director would be short-lived.

Miller also explained that it was rather unusual for the FBI to make such a major decision on its own—normally such a decision on a major case would ultimately be made by Justice Department officials in consultation with the FBI.

"That's a big decision for the FBI," Miller said, underscoring the gravity of such an action. "At the moment when the Department of Justice was under assault, and people were worried that it may never operate the way it was supposed to again, Andy McCabe stood in the breach."

McCabe is a polarizing figure, and many Justice Department officials distrust him based on the agency's Inspector General (IG) report concluding that he displayed a “lack of candor” with investigators about a media leak. McCabe maintains that the IG report was a rush job to reach a political end just before his pension kicked in. "It was the result of a process that was unlike any I have ever seen," McCabe told Deadline’s Wallace.

However well that report and McCabe's dismissal hold up with the passage of time, McCabe appears to have taken an inspired action at a very critical moment in history that helped set the nation on a course toward justice. Whatever the Mueller report (or what's released of it) actually reveals, many ongoing cases in the Southern District of New York and elsewhere were born of the Russia probe. McCabe seems to have helped ensure those ongoing cases would be given life. No wonder Trump has a white-hot hatred in his belly for McCabe.