The elephant in the room of international law

There is a fair amount of literature concerning violations and grave breaches of international law, mostly centered on various Geneva Conventions. For example:

Article 85.-Repression of breaches of this Protocol

3. In addition to the grave breaches defined in Article 11, the following acts shall be regarded as grave breaches of this Protocol, when committed wilfully, in violation of the relevant provisions of this Protocol, and causing death or serious injury to body or health:

(a) Making the civilian population or individual civilians the object of attack;

(b) Launching an indiscriminate attack affecting the civilian population or civilian objects in the knowledge that such attack will cause excessive loss of life, injury to civilians or damage to civilian objects, as defined in Article 57, paragraph 2 (a) (iii);

International law also addresses how those involved in a conflict should treat prisoners from enemies who do not subscribe to Geneva and some other peripheral issues.

And it addresses how war crimes are determined and tried in an international court.

But, as far as I can tell, international law does not address the possibility of one party of a conflict that continuously and explicitly ignores all the norms of war - one that uses its civilians as human shields, one that specifically and deliberately targets civilians, one that would use illegal means such as chemical weapons if it had the means.

In other words, if a state is fighting against a rogue terrorist entity that does not accept Geneva and in fact flouts it, the state still is bound by its own acceptance of Geneva. So terrorists have an automatic advantage in methods and tactics against any signatory of international law conventions.

On the face of it, it seems ridiculous. The purpose of international law of war is to place restrictions on warfare for everyone's benefit, for humanitarian and practical reasons. But if one party has a tactic that violates international law, it would seem reasonable that the war should be fought according to the rules that the violator themselves made. If the violator uses poison gas, for example, they can no longer expect to be protected from being attacked by poison gas.

This does not mean that the state has a right to do anything immoral, and there should be rules restricting what a state can do in this case. But from what I see, interntional law has failed miserably in this regard in the current Lebanon/northern Israel conflict. The idea of an eventual war-crimes trial for Nasrallah being a disincentive for him to continue to endanger Lebanese civlians and target Israeli civilians is laughable.

International law is giving terrorists a great tactical advantage and it needs to address this issue adequately.