Who is Mortimer ("Mort the Wart") Hobart from The Moon Is a Harsh Mistress and what is their importance?

A Federated Nations ex- Senator, Hobart is officially the "Protector of the Lunar Colonies by Appointment of the Lunar Authority," but is generally referred to as "The Warden," in recognition of the fact that Luna is originally used as Terra's convenient penal colony. Hobart himself comes to the moon as a political exile. He gives one speech, and thereafter limits his activities to conducting VIP tours. Mike the Computer controls all aspects of life in Luna, so when he joins the Revolution, he is able to tap Hobart's files and conduct a middle-of-the-night phone campaign that quickly drives Hobart crazy. He demands additional security forces from Authority Earthside, but is turned down. During the actual coup, Mike removes oxygen from Hobart's office, resulting in Hobart's suffering hypoxia. Mike imitates Hobart's voice to convince Earthside he is growing senile, thus setting up the story that he suffers a stroke and is being well cared for.