Despite an apparent determination by the International Court of Justice that complicity under Article 16 ASR can only result from positive acts, it will be argued that a State may be responsible for complicity through passive assistance. Though complicity by omission has received academic acknowledgement, the concept is unduly restricted; posited as contingent on a pre-existing positive obligation to act, and thus necessarily entailing a violation of this primary norm. If this is so, complicity creates a duality of responsibility and is arguably rendered redundant, as it will always be easier to show that a State violated this positive obligation, than successfully leap the many hurdles of Article 16 ASR. This understanding of passive complicity will be challenged on a number of grounds, ultimately leading to the assertion that international law does recognise a useful concept of passive assistance, distinct and untethered from positive obligations. This is termed ‘complicity by inaction’ – passive assistance that is not per se wrongful