It exists. It is the application of international law that seems to be sporadic. The problem is that countries don't all hold the same sway. Traditionally, the veto weilding countries have had the final say, but we now see that the rising superpowers and politcal bloks such as the Arab league and the non-allied nations are shouting louder. As a result, breaking the Geneva conventions is no longer tolerable, whoever the perpertrator. Israel included.
Iran's Parliament speaker says he supports nuclear deal (AP)