In the 1996 advisory opinion on the Legality of the Threat of Use of Nuclear Weapons in Armed Conflict,…

The ICJ found the threat or use of nuclear weapons generally contrary to international humanitarian law but could not conclude definitively as to its lawfulness in an extreme circumstance of self-defence in which a State's very survival is at stake, so the proposition it accepted is that such threat or use "is legal if a state resorts to these weapons when it feels that its very survival is at stake, provided that such use of the weapons conforms to rules relating to self-defence and international humanitarian law".