The Special Counsel's office, nearly leak-proof since its inception more than a year ago and seemingly immune to the President's constant taunts, might appear to be operating in some parallel universe unmoved by the every-day political turmoil. But in the course of conversations I've had recently, as a I research a new book on President Trump and the forces arrayed against him, what has become clear is that Robert Mueller and his office are preparing for a life or death confrontation with the President and the mother of all constitutional crises. My discussions have been with both White House advisors and people close to the investigation. No source involved in this story would speak on the record. But one source allowed me to review some of the documents related to the Special Counsel's strategy. Aspects of the Special Counsel's strategy have been confirmed by both White House sources and lawyers closely involved with the Justice Department. Since at least April the Special Counsel has had in place proposed charges, a bill of particulars, and an aggressive legal theory for the indictment of the president for obstruction of Justice. In the last few weeks, as the President has indulged his pardon authority, the Mueller team has also developed a legal strategy to oppose what the Special Counsel believes will be a likely pardon of former National Security Advisor, Michael Flynn, who had previously struck a plea bargain which could include his testimony against the President. Robert Mueller, according to one person familiar with the Special Counsel's thinking, could hardly contain his disgust when Rudy Giuliani, the President's new lawyer—hired to makes a television case for the President and to push back against the Mueller team—in May airily dismissed the notion that a president can be indicted. Adding insult to injury, Giuliani—who a White House source said had likely learned of aspects of the pending indictment—said Mueller agreed with that assessment. White House sources believe Giuliani was daring the Special Counsel to tip his hand. Mueller, in character, contained his outrage and continued to hold his cards close as his team finished preparing the obstruction case and refined the legal theories under which it would claim the right to haul the president into court. At this point, the case for indictment has, in effect, a judge of one. The Mueller team, according to sources both near the investigation and the White House, has prepared the case, but it requires the approval of Deputy Attorney General Rod Rosenstein, who—with the recusal of Attorney General Jeff Sessions from the Russia-related investigation—oversees the Mueller team. Indeed, Rosenstein, as recently as April, publicly declared that the President was not a target. This may have been a form of fig leaf to soothe a President who regularly demands aides assure him he is not being pursued: the President does not become a formal target until Rosenstein agrees to designate hi m as one. The proposed indictment confronts Rosenstein with matters with which he has been intimately involved. The case, according to my conversations with White House and other sources familiar with the investigation, is fundamentally Trump versus the FBI, Justice Department, and Mueller investigation itself. In many ways, it boils down to the word of former FBI Director James Comey against the word of Donald Trump. Rosenstein, at the President's behest, drafted a memo justifying the Comey firing for how the former FBI Director handled the Hillary Clinton email investigation. But that justification, in an embarrassment for Rosenstein, was shortly brushed aside by the President when he admitted that he fired Comey to disrupt the Russian investigation. What's more, the indictment is said to charge that the firing of Andrew McCabe, the former Deputy Director of the FBI, who reported directly to Rosenstein after the Comey dismissal, was an instance of illegal retaliation by the President against a potential witness. According to a source with knowledge of the proposed indictment, it will be all the more controversial because if finds the entire narrative of the case for obstruction in plain sight. Almost nothing about the case involves new information. "This indictment could have been drafted without anyone being interviewed," said this source. Rather it takes well covered public events and moves them to a set of circumstantial conclusions. There is no smoking gun beyond the often flagrant, custom-breaking, events of the President's 16 months in office. Indeed, much of the evidence is based on the President's public statements and tweets about those events.