The Threshold of Escalation
While Scholz’s caution was evident, one question I raise in the article is: when, if at all, should the presumption against escalation be overridden? Brunstetter argues that in some cases, such as in the Balkans in the 1990s, exceptions to the escalation principle might be justified. However, the situation in Ukraine is unique, with significantly higher stakes, particularly due to the threat of nuclear war. Scholz’s careful balancing act reflected the concern about crossing what Jürgen Habermas calls a risk threshold, a point beyond which escalation becomes uncontrollable.[4] Nevertheless, the need to extend this threshold, rather than viewing it as fixed, also appears to be an important consideration. For example, Sir Patrick Sanders, the former Chief of the General Staff, has argued that the West has sometimes overestimated Russia’s reaction to its support for Ukraine.[5]
The Moral Challenge of Force-Short-of-War
There is another important jus ad vim concept that seems to apply to the supply of weapons to Ukraine, namely, Brunstetter’s concept of moral truncated victory. He argues that force-short-of-war cannot achieve the same moral goods as a full war, which might bring about decisive justice. Rather, the best one can hope for is to contain the conflict or create a limited form of order. In the case of Ukraine, this might mean limiting Russia’s territorial gains without achieving full restoration of Ukraine’s sovereignty.
In the article, I argue that Germany's approach aligns with this idea of moral truncated victory. Scholz’s rhetoric, particularly the notion that “Russia must not win, and Ukraine must not lose,” acknowledged that the best achievable outcome in this context may be a containment of Russian aggression, rather than a complete victory. However, this brings its own set of challenges. The more the war drags on without resolution, the more morally problematic the concept of jus ad vim becomes, as it risks leading to a regime of vis perpetua, or perpetual force, —a situation in which limited force becomes a long-term strategy without a clear end.
Jus ad Vim and the Risk of Perpetual Conflict
The risk of vis perpetua is a significant critique of jus ad vim. Christian Enemark has warned that limited force could become a method of ongoing risk management, leading to a situation where the war never truly ends.[6] Scholz’s strategy, while designed to prevent escalation, risked contributing to such a perpetual conflict, where force is continually applied without resolving the underlying issues.
This challenge was compounded by comments from Western officials like former U.S. Secretary of Defence Lloyd Austin, who have argued that weakening Russia through the war in Ukraine might reduce future threats to NATO.[7] However, if the West, following Scholz’s framing, continues to send weapons to Ukraine solely to prevent Russia from winning without seeking a long-term solution, it risks turning Ukraine into a proxy conflict—a form of perpetual force aimed at containing Russia. This would echo the concerns about preventive use of force, which is often criticised as being incompatible with just war principles.
The Expiry Date Dilemma
Another concern I identify is what I call the expiry date dilemma of jus ad vim. The question of how long Western nations, including Germany, will continue supporting Ukraine militarily remains uncertain, particularly with potential changes in leadership in countries like the U.S. At the time of writing, a second Trump presidency was still a possibility only; now we are discussing the potential fallout of this dilemma on a daily basis. I point to the problematic nature of the expiry dilemma and how it might affect Ukraine’s war effort and lead to the rewarding of Russian aggression if support dwindles over time.
In conclusion, while Scholz’s approach to supporting Ukraine with weapons is morally grounded in the principles of jus ad vim, it faces serious ethical challenges. These include the risk of moral truncated victory, the potential for a regime of perpetual conflict, and the uncertainty surrounding the long-term sustainability of Western support. The balance between avoiding escalation and seeking a just peace remains a delicate and ongoing moral dilemma.