That's why I love Halsey's journal so much. It's such an insight when combined with the other side of the story in Fall of Reach, Reach, and such. Some people liken her to Mengele - I mean, just the other day I was telling a buddy of mine about her whole history and the whole flash clone thing, someone familiar with Halo but not necessarily these gitty details, and he made that connection instantly. What with her thinking her Spartans are the perfect race, with perfect genetics and the perfect tools, etc. etc. I don't think that's entirely how I view her, honestly, but one can certainly make that type of connection.
It's difficult, because everything, every projection, every piece of data that was available to the UNSC pointed toward imminent and absolute self-destruction and perpetual war within humanity's "empire", from Halsey's perspective. And as far as anyone was concerned, Halsey was in THE best position to do something about it, and was basically given carte-blanche to fix the problem. She decided she needed to make the Spartans, the smart AIs, and the Mjolnir suit to connect the both of them together. And then they made first contact, and it turns out, she was correct. Very correct. More correct than anyone had thought. Something no one could have predicted - yet if she hadn't done it, the Covenant likely would have succeeded in wiping out not only the human race, but also in activating the Array and annihilating everything, again.
In order for that to happen, she made questionable moral decisions, and absorbed a lot of the ethical issues and the risk as well - that was her sacrifice. And in most any other circumstance the ends most likely would not have justified the means. But in this case? It's not so clear to me. The debate wouldn't even be happening. It's a strange thought, anyway.
So I'm not one that's ashamed to say that I'm still somehow rooting for Halsey to walk away from all of this (or die from all of this) having her motives in line with the betterment of humanity, instead of just the betterment of her own agendas or pride. With that said, your comment made me consider something I hadn't yet.
I know there are a few of us at least on here who suspect that Halsey possibly has a geas of the Librarian within her, which helped guide her subconsciously to create the Spartans, Cortana, the MJOLNIR systems, the whole shebang. Without giving it much further consideration, I just always assumed that was the extent of the possible geas within her, leading her to create Cortana and Master Chief.
What if that isn't all her geas has in store for her though? I mean, sure, we know she has 1/2 of the Janus Key, and she
is Catherine Halsey, after all, but as far as her place in the Librarian's overarching plan, I hadn't considered what else she could provide humanity/galactic life beyond the Spartan program...but I think there might be some clues that she's still got a major role to play.
It's been known for a good while now that Humanity was meant to take the Mantle of Responsibility instead of the Forerunners. This Mantle is a responsibility to oversee and protect all life in the galaxy, not merely the Mantle's holder's species. As of the events surrounding Halo 4 and following, we have been able to see more clearly than ever that the UNSC, and ONI in particular, is concerned with itself almost completely exclusively. Sure, you've got those like Lord Hood, who seem to desire to have
peace with other species, but peace is not synonymous with concern. The number of characters we've been introduced to that have the best for all life in mind are very slim, indeed. Yet, if humanity is to be propelled to uphold the Mantle, then there
has to be a change of heart, motive, understanding, and action. I believe one such person who is ready and willing to do this could be John-117, especially with further instruction, but I believe another person who is closest to this mindset is none other than our Doctor Halsey.
Halsey has repeatedly shown she is willing to put politics and short-lasting (in scope) moral dilemmas aside for the sake of the "greater good", even when the vast majority (read:99.999% of humanity) would stand against her choices. She is willing to do what has to be done to protect life. She has a responsibility because of her wisdom and insight that no one else has, and she is willing to bear the burden of such responsibility in a heartbeat, without question.
If humanity is truly to take upon itself the Mantle of Responsibility, the UNSC and ONI, in their current perceptions and upholdings, drastically have to change, or else they must move aside in order for humanity to propel itself to where it is meant to be. I think Halsey understands this, better than any other, and I believe she is the one who, once again, is willing to pull the nasty trigger to do what must be done. Maybe this is because her (potential) geas continues to guide her to this point, or maybe she just has an insight and a gut that has led her right so far and therefore continues to follow it. In either case, I believe Halsey to be the example of mindset that the rest of humanity needs if it is to adequately uphold the Mantle as the Precursors designed it.
I was going to buy one a while back, but I couldn't find any in-stores and online I could only find "bargain price" copies (which may have black marker stripes, which I don't want). If I looked hard enough I could find a good copy, but I don't care that much. 
