Kings' Gambit

Kings' Gambit is a quest in Fallout: New Vegas.

Quick Walkthrough
Stop the violince in Freeside against NCR citizens.

Detailed Walkthrough
When you enter the New Vegas Strip for the first time Victor will tell you to go and speak with Mr. House. After you speak to him and exit the Lucky 38 you will be approached by a NCR Trooper (unnamed). He will tell you that you have an important message from Ambassador (Dennis Crocker). This will start the quests needed to get the quest King's Gambit.

Crocker tells you about all the violence in Freeside, this being caused by "The Kings" led by The King. What you can do is choose to kill the whole Kings Gang, kill Pacer with an energy weapon while sneaking, or talk to Colonel Hsu in McCarran Camp about the resources he sends to Freeside, Hsu will make a deal with The King for trade that he will stop the violence on NCR citizens in Freeside for exchange that Freeside will get food, water, and supplies instead of just NCR soldiers receiving the supplies. Pacer, The Kings "right hand man" will be against the deal in "The Kings School of Impersonation" with the NCR, he will try to kill everyone there (don't shoot him it will make the Kings hate you, have the NCR finish him).

Another way to stop the violence without killing or framing anyone of the Kings is to get on the King's good side. You can do this by completing the G.I. Blues quest an ask him to stop violence against the NCR. He will mention it will be a tough job but he will do it. However, if this option is chosen he will also state that this makes you even and you can't choose any of the other rewards for G.I. Blues anymore.

Third way. Talk to a ghoul named Rotface outside Mick and Ralph's in Outer Freeside. He'll give you some pointless hints and tips. Two of which are Pacer has a heart problem too many drugs will kill him and another is he has a feud with the Van Graffs. Go next door and you can have a note from the Van Graffs forged. Go to Pacers room on the third floor; under his bed on the left hand side is his jet stash. You can lace this with psycho to kill him. You may need a Stealth Boy as he never left the room for me. Note cannot be used with the psycho but could be put in the jet box.

Bugs
Bug: If you choose to deal with the The Kings via ultimatum with a squad of NCR troopers, you will not be able to complete the quest as Crocker will register that you killed King instead of following quest orders then killing him.

The quest will be failed and you are then handed the next part of the chain.