Governments and military planners are obsessed with how much leverage adversaries can exert with coercive measures that don’t risk all-out war. But to win in the ‘grey zone’ requires being proactive, and defining its limits.

For over five years Western governments have been staring with a mixture of fascination and horror into the ‘grey zone’ - a space where states uses coercion and force to achieve their goals without risking escalation to direct military conflict. Ever since Russia’s annexation of Crimea in 2014 there has been widespread anxiety over how to manage threats that exploit misinformation and misdirection to circumvent imbalances in military power.

The obsession with the ‘grey zone’ however is becoming unhealthy, and even dangerous. It has become fashionable to argue that future warfare will see armies stopped by cyber attacks before a blow is even struck, while information operations will so devastate a country’s will to fight that governments will be unable to deploy their forces. It is therefore proposed that militaries ought to optimise their structures and capabilities to operate within this non-kinetic space. While Russia’s incursions into Ukraine triggered the popularisation of these theories it is often overlooked that Russia’s annexation was made possible by the direct threat, and eventual application, of massive firepower.

The reality is that ‘grey zone’ operations are very rarely premised on ambiguity or plausible deniability. It was never in doubt that Russia was behind the seizure of Crimea, just as it was obvious that Iran recently conducted a cruise missile strike on Saudi Arabia. Rather such actions are premised on implausible deniability, and this is not intended to provide the perpetrator with an alibi, but rather present the victim with a fig leaf to mask the shame of their inaction. ‘Grey zone’ activity is not made possible by the perennial ambiguities of international politics, but by the opportunities created by our feebleness or apathy. Saudi Arabia was unwilling to explicitly accuse Iran of conducting an armed attack against it because the Saudis felt unable to impose military costs in return without suffering disproportionately in any escalation.

Contrast Saudi Arabia’s inaction with Turkey. On 24 November 2015 a Russian Su-24 violated Turkish airspace for a matter of seconds. It was promptly shot down. There was to be sure a certain amount of gnashing of teeth in Moscow, but there was never any suggestion that the incident would lead to armed conflict. Ultimately the only consequence was that Russia now respects Turkish airspace, a claim that cannot be made of the Baltics, where airspace violations have become routine. The same dynamic was demonstrated following a battle between US forces and Russian Wagner Group troops in Syria in 2018, in which Moscow refused to acknowledge its forces as they crossed a deconfliction line. The US opened fire. The Russians took hundreds of casualties. In Moscow the incident was met with surprise, but there was no threat of retaliation, and a marked decline in infringements of the deconfliction lines. It might be said that if an adversary is using ‘grey zone’ tactics, they are probably trying to avoid escalation, which means imposing a heavy cost is often unlikely to lead to an outbreak of hostilities.

This highlights something fundamental about the ‘grey zone’. We determine its boundaries, and those boundaries can be changed. It is notable that Iran has taken seriously the US’s pronouncements that the death of its nationals will lead to military retaliation. The Iranian Government recognises that killing an American will force the US to respond, and has exerted pressure on its proxies in Iraq to avoid clashes with US forces.

As the recent competition between Washington and Tehran demonstrates, the ability to escalate to a point unacceptable to an adversary, and the threshold at which that escalation will occur, sets the parameters for ‘grey zone’ activity. Tehran can impose a high price on escalation, but would suffer grievously in return. The balance of deterrence fixes the confrontation within understood limits.

Given that hard power, and the willingness to use it, defines the boundaries of grey zone conflict militaries should avoid the mistake of prioritizing operations below the threshold of armed conflict at the expense of conventional capabilities. Against states that are unable to resist there is little compunction at employing violence within the international system. In short the capacity to fight is the reason there are thresholds. As Turkey demonstrated, a state does not need to be more powerful than its adversaries to respond to grey zone activity. It must simply be able to inflict sufficient pain to take force off the table. There is therefore a bounded limit to the military capabilities required to keep competition in the ‘grey zone’.

A further important lesson from the success of US deterrence against Iran in protecting American nationals is that the thresholds were clearly and credibly articulated, publicly, and in advance. In the United Kingdom there is currently a great deal of mutual backslapping in Whitehall over the handling of the attempted Russian assassination of Sergei Skripal. This self-congratulation over the ability to get several bureaucrats who work on the same street in London into a room at the same time seems altogether misplaced. It takes a certain lack of perspective to consider a chemical weapons attack on the UK which killed a British national, hospitalized several more, and tied up the Army’s CBRN capabilities for months, to be a success.

Russia was surprised by the vehemence of the response to the attempted assassination. This suggests that the Kremlin had misjudged how its actions would be perceived. That there was any ambiguity over the UK’s reaction shows how far deterrence and the communication of red lines has deteriorated. Instead of proactively and clearly setting thresholds to signal to adversaries the UK has become reactive, with every new tanker seizure or hostile act a crisis, despite the threat of such actions being patently obvious.

Ultimately it is necessary for the UK to relearn the meaning of conventional deterrence and to resource it appropriately. Today, deterrence is often discussed as a verb. But deterrence is not an action. It is an effect. The foremost question that matters is whether the adversary understands Britain’s red lines, and whether they believe Britain will enforce them. If that cannot be established then by all means expect a torrent of ‘grey zone’ activity. But it is our ineptitude rather than their ingenuity that set the rules of that game.