I don't think Harry's promises work like that, he seemed very earnest about them.
The thing that still gives Harry some room to maneuver is that he still doesn't know if Narcissa Malfoy was burned alive, or if Dumbledore just arranged it to appear that she was burned alive. This was one of the explicitly declared conditions, that if she wasn't burned alive, Harry will get to decide by himself whether to still go ahead with the pledge or not.
And there's also the secondary possibility that she was burned alive, but that it wasn't Dumbledore who arranged it to happen, he just took credit for it afterwards to serve his purpose of protecting the families of the Order of the Phoenix.
If Dumbledore endorsed the burning-alive (even after the fact), then I think Harry's promise requires him to take Dumbledore as an enemy.
That said, I'm not sure that D has endorsed the act, so much as declined to shoot an ally - which isn't quite the same moral position. (Or is it? Have to think about that).
The new discussion thread (part 15) is here.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 82. The previous thread passed 1000 comments as of the time of this writing, and so has long passed 500. Comment in the 13th thread until you read chapter 82.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13.
As a reminder, it’s often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: