Military denial: the basis of deterrence, and of response if deterrence fails
A strategy of denial is now the cornerstone concept for Australia’s National Defence Strategy. The term’s use as an overarching guide to defence policy, however, has led to some confusion on what it actually means in tangible, military terms.
According to the 2024 National Defence Strategy, the core aim of the strategy is to thwart our adversaries’ objectives through deterrence by denial—meaning to make the other side think its objectives are militarily unachievable without great costs. The practical capacity to do this is called ‘military denial’.
It now falls to Australian policy makers and planners to consider how strong a capacity for military denial we need—how robust our military capability to actually deny an adversary must be to achieve our broader aim of deterrence and to respond to its potential failure.
As two historical case studies in this article show, deterrence fails without persuasive capacity for military denial. And if it does fail, actual military denial is the foundation of response.
Degradation of a strategy of denial: the interwar Singapore Strategy
After nearly 20 years of defence planning, the 1942 collapse of the British and Commonwealth position in the Far East became a pivotal moment in the early phases of the war in the Pacific and in British military history.
Britain had devoted great resources following World War I to a strategy of deterring Japanese incursions into British territories through a credible capacity to apply military denial. Known as the Singapore Strategy, this involved building a naval base large enough to support and supply a British naval fleet in the region. In the event of war, the Royal Navy’s main fleet would head east from Singapore to overmatch and neutralise Japanese naval power. It would use either economic pressure through blockade or engage in a prolonged conflict of attrition. Through its ability to facilitate powerful and credible actions of military denial, the Singapore Strategy would serve as a deterrent, pressuring Japan to reconsider military actions against Commonwealth nations.
In the 1920s, however, fiscal limitations led to noticeable decline in relative British naval strength. Strategy shifted from maintaining global naval superiority to achieving dominance mainly in European waters. Only the main fleet, located in Europe, was strong enough to confront the Imperial Japanese Navy. As the threat from a revitalised Germany grew during the 1930s, it became impossible to contemplate deploying the entire main fleet to the Far East without risking the security of the Britain and its territories in the Middle East.
The newly established Singapore Naval Base therefore had no fleet ready for deployment. The credibility of the Royal Navy’s threat to apply military denial declined, with a consequent loss of deterrence effect. There remained optimism in London that the land and air elements of the Singapore strategy could deny a possible Japanese advance. The strategy informally pivoted from naval denial to relying on aerial and ground forces to counter potential aggression against the Malay Peninsula.
By 1941, the planned British fleet response was not available to use the base, nor was there a strong enough air force to deny offensives against the peninsula. Only the land forces on the ground remained to hold and physically deny the Japanese the ability to capture it. The original Singapore Strategy, however, had not prioritised the preparedness of the land forces on the peninsula. In optimistic assessments in 1940 nine land brigades would be enough to deny Singapore to the Japanese. With Japanese encroachment in the region, by late 1941, Lieutenant General Arthur Percival revised this higher, to a requirement for 48 battalions with armoured support. These forces were unavailable. Singapore fell to the Japanese on 15 February 1942.
The fall of Singapore offers lessons around the role of military denial in deterrence. London failed to recognise the impact that the loss of a credible naval capacity for military denial had on the strength of deterrence. It overestimated the deterrent effect of bases alone, underestimated Japanese resolve and failed to prepare replacement forces to fill the military-denial gap as British naval power faded. When deterrence failed, the British government was fatally unable to generate sufficient or credible military forces for the actual—physical—military denial of Singapore to the Japanese. The result was catastrophic.
Denial when deterrence fails: military denial at Kyiv, 2022
Despite increasing capability since 2014, the Ukrainian government and Armed Forces of Ukraine (AFU) failed to deter Russia’s invasion in 2022. Ukraine’s immediate response to the invasion, however, exemplified a successful military denial of Russian objectives. The AFU skilfully executed this strategy, even in the face of a near-fatal surprise at the operational level from the main Russian attack.
A central element of Russia’s military plan was to capture Kyiv in three to four days with coordinated airborne and mechanised forces. The Ukrainians recognised this, and when deterrence failed, they fought aggressively to deny the Russians their initial objectives. The AFU used initiative and tactical adaptation to initially slow the Russian advance on the Gomel and Chernihiv-Sumy fronts, overcoming a 12-to-1 force disparity between defenders and aggressors. They then exploited operational adaptability, bolstered by artillery support and modernised systems acquired since the 2014 annexation of Crimea and conflict in Donbas, to shift to military denial around Kiev.
The Battle for Hostomel Airport exemplified the AFU’s effective application of military denial. Russian planners chose the airfield as a target due to its proximity to Kyiv, its location along the Gomel axis of advance and because of lacked defences. It was a military airfield with a 3,500-metre long runway and could support large transport aircraft. The Russian operational plan called for a rapid air assault. A company-size contingent of Russian troops conducted a successful air-mobile assault in transport helicopters in two waves and quickly began to take control of the control tower and adjacent airfield administrative buildings.
AFU leadership immediately recognised the strategic importance of the airstrip and ordered a counterattack to deny it to the enemy. The AFU aggressively fixed Russian forces at the airfield and then rendered it unusable through artillery strikes and aerial bombardment, cratering the runway before withdrawing. A lack of an air bridge significantly hampered Russia’s logistic system. By applying effective military denial at Hostomel, the AFU denied the Russians the ability to hold key terrain, expand their foothold or link up with penetrating armoured forces.
As the Russians saw their offensive falter and faced the possibility of encirclement by Ukrainian counterattacks, they withdrew from Kyiv Oblast, leading to an initial Ukrainian victory. The application of credible and effective military denial prevented Russian forces from consolidating, forcing them to abandon their objective of swiftly subjugating Ukraine and decapitating the Zelensky regime in Kyiv. Like Singapore, Russia’s invasion of Ukraine demonstrates a failure of deterrence by denial. Nevertheless, it also reflects the criticality of still being able to achieve actual military denial should deterrence fail. The AFU’s capacity for military denial was their saviour.
Learning from history
The case studies above suggest that credible and relevant capacity for military denial is the foundation of an effective strategy of deterrence. It is then just as important in responding when deterrence fails.
In Singapore, the British underestimated their declining credibility in military denial and misread the effect this had on the strength of deterrence. Even worse, they failed to prepare sufficient forces to respond when deterrence failed. They instead fell foul to political and bureaucratic frugality, faulty planning assumptions, poor coalition cooperation and a fatal underestimation of their enemy. They fundamentally lacked the ability to transition from deterrence by denial to actual military denial, leading to one of the most profound losses in British military history.
In the Ukrainian example, the AFU lacked sufficient capacity in military denial to effectively deter the Russians from invading. However, when deterrence failed, they had credible, relevant and prepared forces ready to actually deny the objectives of the Russian Armed Forces in the immediate transition to war. Evidence shows that the Ukrainians expected deterrence to hold and that the Russians would not invade. This was wrong. Nevertheless, they were ready to respond to this error in a manner that ultimately saved Kiev, and prevented a Russian coup de main.
The critical lesson is that a strategy of deterrence by denial rests on a credible capability for military denial. Without credible capability, deterrence is nothing more than an illusion: one that a sophisticated adversary will quickly see through. When deterrence fails, it is important that states in our region then possess the integrated, credible and relevant capability to actually deny objectives to an enemy, even if only in the short term. The only alternatives will be defeat or surrender.