@ZachBitango These, or their successors, remain in command until a formal Joint Command or Unified Command is established. The politicians are usually told to sit in a corner and speak when told.
@ZachBitango FEMA's IS-100 or IS-200 states that the Public Information Officer determines the order of public briefings. The PIO reports to the incident commander, who is almost always the first police or fireman on the scene.