The Contingency Orders for the Grand Army of the Republic: Order Initiation, Orders 1 Through 150 was a compilation of contingency orders that were to be carried out under various circumstances by the Grand Army of the Republic. Any clones found in violation of any of these orders, especially Clone Commanders, would be stripped of their rank and rendered subject to execution.
In addition to the known orders, in the aftermath of the Galactic Empire’s rise to power, the newly christened Sith Lord Darth Vader came to suspect that his master, the Sith Lord Darth Sidious—known to the galaxy as the newly crowned Emperor Palpatine—had developed a new contingency order (Order 151) to eliminate him should the need arise. Lord Vader questioned Clone Commander Vill, referencing the contingency orders the clone had known while a part of the Grand Army before the Republic’s fall. When the officer indicated that he was unauthorized to confirm or deny the existence of any such order, Vader considered his suspicions confirmed and quickly dispatched Vill so as not to alert the Emperor of his inquiry.[3]
Although technically not part of the Contingency Orders for the Grand Army of the Republic due to it being used exclusively with the Separatists, a similarly named order called Order 99 existed among its forces, which made the droids move to the opposing side. The order was developed as a test for the later Order 66 for the clone troopers to use against the Jedi.