Once the player character arrives at the town of Nipton, a man will approach the courier and happily inform them that he has won the lottery. Upon further exploration through the rubble, it can be determined that the Powder gangers, who once took this town, have now suffered the fate of crucifixion. After moving further toward the town center, Caesar's Legion members can be seen gathering near the double doors of the town hall. Upon approaching the Legionaries, Vulpes Inculta will approach the player character and begin a conversation. Vulpes informs the player character that he will "not have you lashed to a cross like the rest of the degenerates." Inculta instructs the player character to then travel to the Mojave Outpost and let "the Profligates" know "the little sermon" he prepared here. By telling Vulpes that his actions were respectable, the player character can gain Legion fame.
Travel west to the highway intersection, then southwest, following the highway up the hill to Mojave Outpost. Two large statues of Rangers shaking hands can be seen from a good distance. Sgt. Kilborn walks around outside and occasionally paths past the statues out of range of the rest of the outpost. When speaking to him, the Courier can either inform him of Nipton's destruction or shout a Legion battle-cry and attack him. Either choice completes the quest, resulting in 150XP. No reputation is gained or lost either way.
Note: Selecting the attack choice in the dialogue may turn the rest of the outpost hostile if Kilborn is not far enough away from them. As long as he is near or past the Ranger statues, it should be safe to kill him. Also worth noting, if the player character selects the attack option while wearing NCR faction armor, Kilborn will not attack the player character and the quest will complete normally.