As negotiations continue between Robert Mueller and Rudy Giuliani over a potential sit-down interview with President Donald Trump, Giuliani has gone on a public-relations tour announcing that he has offered to bring the president in to speak with Mueller, under certain (unspecified but certainly wildly self-serving) conditions. According to Giuliani, it is now up to Mueller to accept or reject those proposed conditions. Some have likened the back-and-forth to a chess match, but it’s more like the parties are actually playing two different games: Mueller is playing the legal game while Giuliani is playing a political one.
Anytime a prosecutor wants to speak with a person about a criminal matter, there’s an easy way (an interview) and a hard way (a subpoena). In an interview, the subject agrees to come in to the prosecutor’s office, typically with a lawyer, and answer questions from the prosecutor. There is no grand jury or stenographer, and the witness is not placed under oath. Notwithstanding the relatively informal setting, if a subject lies, he can be prosecuted for making false statements. Martha Stewart famously was charged, convicted, and imprisoned not because she lied under oath in a grand jury but because she lied to a prosecutor in an interview.
https://www.thedailybeast.com/trump-will-fold-if-mueller-calls-his-bluff-giuliani-is-the-tell?ref=home