"First, a traditional prosecution or declination decision entails a binary determination to initiate or decline a prosecution, but we determined not to make a traditional prosecutorial judgment. The (OLC) has issued an opinion finding that "the indictment or criminal prosecution of a sitting President would impermissibly undermine the capacity of the executive branch to perform its constitutionally assigned functions" in violation of "the constitutional separation of powers." ...[T]his Office accepted OLC's legal conclusion for the purpose of exercising prosecutorial jurisdiction. ...[W]e recognized that a federal criminal accusation against a sitting President would place burdens on the President's capacity to govern and potentially preempt constitutional processes for addressing presidential misconduct."