In the Imperium there exists the "principle of the individual," noble but
rarely utilized, whereby a person who violates a written law in a situation of
extreme peril or need can request a special session of the court of
jurisdiction in order to explain and support the necessity of his actions. A
number of legal procedures derive from this principle, among them the Drey
Jury, the Blind Tribunal, and the Trial by Forfeiture.
-Law of the Imperium: Commentaries
The written Law of the Imperium cannot be changed, no matter which Great House
holds dominion or which Emperor sits on the Golden Lion Throne. The documents
of the Imperial Constitution have been established for thousands of years.
This is not to say that each regime is legally identical; the variations stem
from subtleties of interpretation and from microscopic loopholes that become
large enough to drive a Heighliner through.
-Law of the Imperium: Commentaries and Rebuttals