Jus in vi

Jus in vi is the set of moral principles governing how limited force is used. Taking the traditionalist jus in bello principles as a starting point, this chapter interrogates what necessity, proportionality, and distinction look like in a limited force context and makes the case for the novel psychological risk principle by evaluating how concepts such as “excessive,” “military advantage,” and “harms” and “goods” fit into our thinking about vim. The keystone of jus in vi is the predisposition toward maximal restraint maxim. The chapter thus begins by making the case for why jus in vi principles should be more restrictive than their jus in bello counterparts. It continues by exploring how a circumscribed view of necessity sets the groundwork for constraining proportionality calculations and shaping the way we think about distinction in more restricted ways. The notion of jus in vi proportionality is then explored, with concerns about escalation and psychological risk driving the analysis. Drawing insights from revisionist just war theory to consider jus in vi distinction, the chapter concludes by making the case for affording greater protections to both combatants and non-combatants compared to standard just war accounts. Unlike war, in which almost any soldier can be targeted, in a context of limited force only those who are an active threat can be justly targeted. Both innocent non-combatants and non-threatening combatants should be preserved from the more predictable harms of limited force, though this differs depending on whether the use of limited force is protective, preventive, or punitive.