ONI Directive 930

ONI Directive 930 is a UNSC regulation pertaining to publicity of the SPARTAN-II supersoldiers. It created a tradition which eventually extended to the SPARTAN-III's as well.

When the UNSC went public with the SPARTAN-II program, the Office of Naval Intelligence, Section Two, issued a directive to falsify the circumstances surrounding the deaths of any Spartans. This was because they feared that the reports of Spartan losses would cause a crippling loss of morale through the UNSC. This protocol creates and maintains the idea that Spartans can't die and that they never have or will. This has led to the common use of the bitterly ironic phrase "Spartans never die" among the Spartans themselves. This has not gone unnoticed by the Covenant, as several times, Prophets refer to Spartans as "demons", due to their ability to kill thousands of Covenant at a time without injury.

The Protocol
Office of Naval Intelligence Section Two Directive 930

To maintain morale among the forces of the UNSC, any Spartan casualties are to be listed as Missing In Action (MIA) or Wounded In Action (WIA), but never Killed In Action (KIA).

SPARTAN-III
Just before his death, ex-Spartan-II Lieutenant Commander Kurt Ambrose lists the status of two deceased SPARTAN-III's as MIA, "adhering to the tradition of never listing a fallen Spartan as 'killed in action' ". However, this was likely more sentimental than official, as the MIA directive was specific to the SPARTAN-II's publicity, whereas the SPARTAN-III Program was designed to never go public. If it did the morale of people would plummet and the people's faith in the UNSC would be gone for good.