Hrm. It gets rather difficult to generalize because a zakhrehain is probably the least defined of the types of war. Leaving aside flower wars and pest control, the defining characteristic of a zakhrehain is simply that it’s not a teirhain.
To be specific, the universally applicable part of the Ley Accords is only chapter one, on forbidden instruments of regrettable necessity. Chapters II-XVI, the Conventions of Galactic Warfare, are a purely reciprocal treaty (and one which in any case binds only those who are signatories to it, or who make a point of announcing at the opening of hostilities that they intend to abide by it). Those chapters are essentially identical to the Empire’s Conventions of Civilized Warfare, which are what define a teirhain. Summary here, for anyone who might need one; there are certain other customs and attachments that Imperial generals, in particular, attach to it such as offering the opportunity to avoid city fighting altogether, as in Civilized Warfare | The Associated Worlds (eldraeverse.com), to avoid “any unnecessary effusion of blood”.
Technically, if you aren’t fighting according to the Conventions of Civilized Warfare, you’ve left just about everything on the table for your opponent, from fighting by the conventions anyway through to total war.
But while that’s permissible, the Empire has its own Conventions of Uncivilized Warfare, which it tends to stick to even if a lot of the details are left up to “Warmain’s discretion”. Most of the variations from the CCW fall into the categories of “obviously we can’t trust the enemy to keep their word” (so, not going to see the above type of gentlesoph’s agreements, and parole is off the table, for example) and “ungentlesophly but expedient” (performing static analysis on prisoners’ mind-states - which doesn’t actually harm them, note - is allowed, for example, as are strategic strikes to induce surrender in extreme cases).
In terms of reciprocity and where it gets ugly to our sensibilities, on the other hand, is largely a matter of quarter. Some of this is fairly direct: if you’re in the habit of booby-trapping corpses and/or of having your wounded attack the medicos, you needn’t expect medical courtesies. Less directly, under zakhrehain rules, when fighting people whose practices involve the routine abuse of prisoners of war, for example, it is considered appropriate reciprocity simply not to take any. Likewise, when dealing with the atrocity-as-policy mob, the IL officially considers it rather pointless to offer quarter to people whom it will only have to go to the time and trouble of formally court-martialing and executing later on. [This last policy is often applied at the unit level, when appropriate.]
(Of course, it might also be argued that this isn’t a change in the rules, technically. The Empire’s legal interpretation of the Conventions of Civilized Warfare is clear; soldiers [including partisans] are entitled to quarter and honorable surrender. Brigands are not. Anyone who abuses prisoners, commits atrocities against civilians, etc., is ipso facto, a brigand subject to summary execution.)
Taking a brief note here to clarify that said spies, assassins and saboteurs are only protected as long as they’re operating against legitimate military targets, and while hiding among the population is protected insofar as it’s the means of the profession, taking hostages, using civilians as shields, etc. is not.
tl;dr Legitimizing these is acknowledging that, well, everybody does it even if they officially pretend not to, but civilized standards must be upheld even in ungentlemanly warfare.
A thing worth noting at this point, considering Civilized Warfare | The Associated Worlds (eldraeverse.com) again, is just how much these policies depend on reputation.
The Empire has spent a lot of time establishing its reputation in various areas, and most specifically that it always keeps its word. Even when it’s difficult or expensive, even when it’s not expedient, and yes, even when it really doesn’t want to. Even if you’re at war with them, you can still take that promise to the bank. The Lannisters only wish they had this much of a rep for always paying their debts.
I mention this as a preeamble, because it’s relevant to the ethics here:
When they say “Your personal freedoms and property rights will be respected,” they mean every word. In hypothetically executing on this doctrine, your property absolutely will be protected and returned to you and you will be entirely safe [from them] in the course of transit to and a hopefully brief stay in the designated safe camp, followed by a return to your home. And their reputation absolutely backs that up, even when they’re dealing with people they really, really loathe.
It’s not intended to be a displacement, it’s intended to be an expedient way of sorting through the categories of “brigand” (who become ingloriously dead), “partisan” (who achieve either death in battle or the opportunity to surrender honorably and become prisoners of war), and “civilian” (who get an admittedly imperfectly comfortable vacation at Imperial expense) without turning it into an impossibly prolonged urban shitfest that’s going to turn a lot of the third category (and their homes) into collateral damage, which no-one should want.
The pitch to those in the category of
is along the lines of “Look, you know us, or you ought to. You know our reputation. You know that we would be, within the strictures of the Ley Accords, permitted to clean up this mess by turning the entire goddamn city into a lechatelierite puddle. But we’re trying, Ringo. We’re trying real hard to be the shepherd.”
