Operationalising the Constrain Concept: Competing Below the Threshold

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This paper aims to operationalise the concept of constraint operations in sub-threshold competition.

The subject of competition beneath the threshold of conflict has become increasingly central to both academic discussions of strategy and policy discourse. Central to this is the idea that adversaries are achieving strategic progress through a series of steps short of warfare, and that crafting tailored responses to this form of coercion is one of the cardinal challenges facing Western militaries. This has found expression in documents such as the UK Ministry of Defence’s Integrated Operating Concept (IOpC), which stresses the need to constrain opponents below the threshold of conflict.

While a focus on competition below the threshold of conflict is an important conceptual development, in order for it to be translated into concrete guidance for action, greater specificity is required on two counts. First, the contours of the sub-threshold space and their relationship to warfighting need to be more explicitly articulated. The criteria for what constitutes sub-threshold aggression are not objectively defined and are typically the subject of a parallel competition to define thresholds in a way that aligns with a state’s own advantages. Second, the pathways by which competition below the threshold of warfare can deliver strategic effects need to be more explicitly identified. If it is indeed the case that states will need to adapt to a mindset of persistent campaigning, then a clearly defined set of campaign goals will be crucial.

This paper seeks to further the evolution of the constrain concept into lines of effort by providing both a discussion of the relationship between constraint and warfighting and a typology of the campaign objectives that can be fruitfully sought below the threshold of conflict. Its key findings are:

  • The boundaries of the sub-threshold space are the product of mutual consent on the part of adversaries. Often, they result from a parallel – and crucial – contest to compel an adversary to define conflict on one’s own terms. This contest is shaped, in no small part, by one’s posture for the use of force above the threshold of conflict and the way it shapes the other party’s risk calculus. Other contextual factors, such as the trajectory of the overall relationship between adversaries, may also play a role in defining the contours of the competitive space.
  • The defining objective of sub-threshold competition is not merely undercutting an opponent’s credibility, despite the outsized importance attributed to this aim. Rather, sub-threshold campaigns can serve several goals, including strategic erosion, tipping the balance in favour of a partner that is in the fight phase of operations, costly signalling and preparing for warfighting on favourable terms.
  • Many of these objectives may be served using capabilities associated with the high-intensity phase of conflict – underscoring the importance of not conflating sub-threshold competition exclusively with specific organisations and capabilities such as special forces or cyber assets.
  • In an operating environment characterised by defence dominance and mutual interdependence among adversaries, the threshold for what constitutes an act of war is likely to be raised, with a range of kinetic actions falling within the sub-threshold space.


Dr Sidharth Kaushal

Research Fellow, Sea Power

Military Sciences

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