It matters here because my top level comment was a reply to someone emphatically stating there is no difference between the actions of the US and IS and I disagree. I believe there is a difference in the actions of US and IS, I used the law to distinguish between two acts. If someone said there was not a difference between the act of 1st degree murder and manslaughter, I would disagree and turn to the law to give examples of the differences.

>That's not what disturbs me. What disturbs me is the notion that a formal law in any way determines the acceptability of a violent act.

No doubt, to many laws of war is an oxymoron. However, the laws don't determine what the acceptable violent acts are, instead humankind determines what is not acceptable based on International consensus and through the treaty/UN we codify it into law.

One example, humans decided land mines as a weapon of war were to indiscriminate and had potential to far outlast armed conflicts and were outlawed by treaty and then codified into a UN Resolution, every year since then annual deaths of landmines has decreased from ~10k/year down to ~3.5k/year. Moreover, often times these laws of war have nothing to do with violence, but make sense such as requiring all military actors in armed conflict to be identified by uniform so as to be distinguished from civilians. Other laws such as Arms Reduction Treaty lead to Russia/US disposing of some combined 50-60k nukes.