After Wednesday’s abrupt post-election firing of Attorney General Jeff Sessions, there are mounting questions about the legal landscape surrounding President Trump and special counsel Robert Mueller’s investigation into Russian interference in the 2016 presidential election.

Many observers and experts expect the probe could conclude with a report by Mueller and both the timing and contents of that document have become sources of intense speculation.

The belief Mueller will issue a report stems from the widely-held view in the Department of Justice and the broader legal community that the indictment of a president in office is unconstitutional. A memorandum on the subject prepared by the Justice Department’s Office of Legal Counsel (OLC) in 2000 flatly declared, “the indictment or criminal prosecution of a sitting president would unconstitutionally undermine the capacity of the executive branch to perform its constitutionally assigned functions.”