I'm having issues getting the Great Khans to ally with the NCR during the Oh My Papa/ For The Republic, Part 2 quests. If I kill Papa Khan after completing the quest by persuading him to perform a suicide attack on the Legion, then kill him, no new dialogue options with Regis appears. If I kill Papa Khan before completing Oh My Papa, the quest is failed BUT no new dialogue options with Regis appear. As I've never tried this option before, I have no way of telling if it's a bug or if I'm doing something wrong.

What should be the correct sequence of actions to get the alliance option?

The only way to get the alliance with NCR is to kill Papa. My character wouldn't do it. I think the ending for the Khans is better without the alliance anyway. I just get them to not keep the alliance with the Legion and sometimes do the part about the Khans history. If you look at the Wiki, you can see the different endings and choose the way you want to go with this quest. Good luck.

http://fallout.wikia.com/wiki/Oh_My_Papa

Kicenna, thanks for your help (you're one of the most helpful people here), but I adhere firmly to the RTFM principle. If I ask a question, it is because I haven't found the answer in the Wiki

My question is about WHEN I should kill Papa Khan to make the alliance happen. I seem to get the option for alliance neither before nor after the completion of the quest.

Thank you. There are a lot of good and helpful people here and that's why I stay...and I love the game. I guess all I can share is that Oh My Papa was the game-ender for my first character last Oct/Nov. The quest has been very bugged and I can't say how many bugs are gone because I don't do all the options. I know that when Colonel Moore said to get rid of the Khans and I decided I didn't want to assassinate Papa, I went back to Colonel Moore and there were no speech options to move on at all because I had spoken to Papa way early in the game before I had gotten the quest and had used up the speech option that was needed. We're supposed to speak with everyone in case it leads somewhere and it made me afraid to speak to anyone unless I was in a quest. I think much of that was fixed in the last patch but I just don't know. If there's anyway to load an earlier save and redo all that you've done (I hope it isn't too many hours), maybe that's the answer...or maybe someone else knows. Like I said, I like the ending for the Khans with the path I took to not assassinate Papa. No answer on the Wiki? Oh no...I'm scared now. :unsure:

Good luck! ( Have you looked around in the bug report forums?)

I will say this, if you care about the Khans you won't let them ally with anyone.

You can get the Khans to ally with the NCR without assassinating Papa Khan. You will need a high speech for this as it requires two checks at 75 skill:

1) Get quest to exterminate them from Col.Moore
2) Talk to Papa Khan, he will refuse to break the current alliance with Caesar.
3) Upon leaving the longhouse, Regis will speak to you and ask you to get PK's other lieutentants to speak in favor of breaking the alliance with Caesar.
4) After doing this, but before talking to PK again, swipe the journal from Karl's locker (this is easy to do if he's not in the room).
5) Present the journal to PK as evidence that Caesar considers them expendable. This will get him pissed and he will have Karl killed.
6) Talk to him again, and use the speech checks, this will give you the option to either ally with the NCR or tell them to get the hell out of Dodge. Choose the 'ally' option and they will send troops to the dam.

When you report back to Col. Moore after finishing this quest you will only have the option to tell her that you wiped them out, but the game will know otherwise and the ending slides will reflect the actual result of the quest.