Escalation

On February 5th, 2026, the last arms reduction treaty between the US and Russia expired. The New Start treaty had reduced Russian and US nuclear warheads and delivery mechanisms. The expiry of the New Start treaty thus constitutes the latest manifestation of what appears to be a continuous escalation in foreign and security politics. Against this background, this instalment of EPIS Basics looks at the concept of escalation. Escalation denotes an increase in the severity of relations among actors and can take multiple forms, depending on the domain. In this contribution, escalation will be examined in the military domain. Specifically, the following paragraphs describe military escalation as occurring along one of, or a combination of, the three dimensions identified by Morgan et al. (2008) in their book “Dangerous Thresholds”.

Vertical Escalation

Analysts speak of vertical escalation if an actor increases the number of attacks, the number of targets, or changes the type of target. Alternatively, a belligerent might also employ new weapons. Vertical escalation is, thereby, assessed against both material and normative yardsticks. For example, the use of nuclear weapons, as threatened by Russia in its war in Ukraine, would constitute an escalation not only due to its increased lethality. Instead, the use of nuclear weapons also constitutes a vertical escalation due to the violation of the norm on the non-use of nuclear weapons. Similarly, the engagement of new types of targets might be deemed escalatory owing to both the military and symbolic value of the targets.

Horizontal Escalation

In addition to vertical escalation, a conflict can escalate horizontally by increasing its geographic scope. A military might continue to engage the same type and number of targets but do so in other geographic locations. For instance, Ukraine’s targeting of military facilities further inland in Russia has constituted a horizontal escalation.

Political Escalation

As military means serve political ends, military escalation might occur through a change in the political ends. In cases where the political objectives are increased, political rhetoric is sharpened, and rules of engagement are loosened, Morgen et al (2008) speak of political escalation. Often, a political escalation is achieved by combining political with horizontal or vertical escalation. To illustrate, the German declaration of unrestricted U-boat warfare in the First and Second World Wars allowed German U-boats to target civilian and military ships of belligerents and neutrals. Political escalation was, thereby, achieved through a vertical escalation in the types of targets.

Escalation as a Tool of Analysis

This publication has examined escalation only in the military context. Nevertheless, even when limited to military matters, the dimensions of escalation provide an invaluable tool for mapping the military options and their consequences in times of war. But even outside the conduct of war, the dimensions of escalation can provide an intriguing insight into deterrence. After all, deterrence seeks to prevent war by threatening escalation. As such, the concept of escalation constitutes an essential bedrock for understanding an increasingly hostile international system.

Recommended Literature

Radin, A., Demus, A., & Evans, A. T. (2024). A vocabulary of escalation: A primer on the escalation literature for military planners. Rand Corporation. https://www.rand.org/content/dam/rand/pubs/research_reports/RRA1900/RRA1933-1/RAND_RRA1933-1.pdf