jats:titleAbstract</jats:title> jats:pThe primary rules of international law do not permit states to resort to force for humanitarian purposes. Some scholars have thus attempted to rely on the secondary rules of state responsibility to find a legal basis for forcible humanitarian intervention. In particular, three claims can be identified: that humanitarian intervention is justified; that the state intervening for humanitarian purposes is excused; and that the consequences arising from the intervention for the state acting for humanitarian purposes ought to be mitigated. All three arguments rely either on the defence of necessity, cast as a justification or as an excuse, or on necessity-like reasoning, as the basis for mitigation. This article takes these three claims and draws out the implications of each both within and beyond the law of responsibility. In so doing, this article shows how each of the three arguments is more problematic and less straightforward than it appears at first and that, ultimately, none can provide an adequate legal basis for humanitarian intervention. The legality of humanitarian intervention must be found in the primary rules regulating the use of force in international relations and not in the secondary rules of state responsibility.</jats:p>