This chapter confronts a central argument of the OLC and proponents of presidential immunity that subjecting a President to criminal prosecution and compulsory judicial process would violate the separation of powers. Judicial and historic precedent are to the contrary. The proponents’ argument, grounded on the theory of a “unitary executive,” that prosecution would put the entire Executive Branch at the “mercy” of the Judiciary is contradicted by Chief Justice Marshall’s actions in the Burr treason trial and the Supreme Court’s decisions in the Nixon, Clinton and Trump cases, which upheld the judiciary’s authority over the President when necessary to vindicate a court’s processes in criminal cases.