Abstract The article addresses three aspects of the humanitarian intervention doctrine. It argues, first, that the value of sovereignty rests on the justified social processes of the target state ? the horizontal contract. Foreign interventions, even when otherwise justified, must respect the horizontal contract. In contrast, morally objectionable social processes (such as the subjection of women) are not protected by sovereignty (intervention, of course, may be banned for other reasons). In addition, tyrants have no moral protection against interventions directed at (...) them. Second, the article addresses the internal legitimacy of humanitarian intervention. It concludes that the liberal state may only use voluntary soldiers (either the voluntary army or mercenaries) to conduct humanitarian intervention. Conscription for that purpose is not permissible. The article shows that the long-standing criticism of mercenaries stems from a romantic prejudice and is thus unfair. Third, the article makes a distinction between intention (the determination to perform an action) and motive (a further goal that the agent seeks with that action) and shows that only intention is relevant for humanitarian intervention. A justified humanitarian intervention requires the intention to liberate the victims, but not necessarily a good further motive. It shows how mainstream doctrine has impermissibly confused the two concepts. (shrink)