Order 5 was one of 150 contingency orders that the clone troopers of the Grand Army of the Republic were trained to implement for several different emergency scenarios during the Clone Wars. Order 5 dictated that if the Republic Supreme Chancellor—an office held by Palpatine—was to be declared unfit to lead the Grand Army, the Chief of Defense Staff would take command of the army until an alternative authority was determined.
Order 5 was the fifth of 150 contingency orders created by the Grand Army of the Republic during the Clone Wars. The 150 contingency orders dealt with an assortment of emergency circumstances that the Galactic Republic might confront during the war. As such, all clone troopers of the Grand Army were trained to execute Order 5 without a moment's hesitation.
Order 5 stated that if Supreme Chancellor Palpatine—the Supreme Commander of the Grand Army—was deemed unfit to direct the army, then the Republic Chief of Defense Staff would take command of it. The Chief of Defense Staff would then form a command structure with a group of senior Republic officers, and would be relieved from command once a new Supreme Chancellor was elected by the Galactic Senate or an alternative Supreme Commander was identified.
Between 20 BBY and 19 BBY, 995 days after the First Battle of Geonosis, clone commando RC-3222 indirectly mentioned Order 5, along with the rest of the Grand Army's 150 contingency orders, to General Etain Tur-Mukan and squadmate RC-5108/8843 during a conversation at the Republic's Special Operations Brigade Headquarters on the galactic capital planet of Coruscant.
Order 5 was first mentioned in Republic Commando: True Colors, the third novel in the Republic Commando series, written by Karen Traviss and published in 2007.