On September 24 (Thursday), Defence Minister Rajnath Singh cautioned against viewing national security solely from the view of safeguarding geographical boundaries, stating that it would amount to what he termed as the “perimeter fallacy”.He made this argument while pointing to the evolving nature of modern-day challenges — drones, cyberattacks, lone wolf attacks, and disinformation campaigns, in addition to the use of arms and artillery, by adversaries.The Defence Minister also said national security is linked to economic and energy security and that India’s approach to containing threats is evolving from “deterrence by denial” and to “deterrence by punishment”.What do these terms — “perimeter fallacy”, “deterrence by denial” and “deterrence by punishment” — mean? What implications does this have for India’s security approach? We explain.First, what is a ‘perimeter’ in this context? And what is the fallacy referred to?Simply put, a perimeter in a security context is the physical boundary of the State in question. Traditionally, national security has placed emphasis on the prevention of the violation of such boundaries by adversaries. This has largely been dependent upon fortifications at the border and troop deployments.The fallacy, which Singh spoke about, comes into play when that physical border is treated as the absolute limit of a nation’s security vulnerabilities.Story continues below this adWhile territorial borders remain geographically fixed, modern threats are highly fluid. For instance, Ukraine’s energy infrastructure has been systematically targeted by Russian hackers since the start of the Russia-Ukraine war, and Poland has faced similar attacks, including one in December that aimed to disrupt the communication between renewable energy installations and power distribution operators, according to a Reuters report.Similarly, the Union Home Ministry had informed Parliament in 2023 that drones were being used to smuggle arms from Pakistan to India through the Punjab border. A government statement from March 2023 said that in the three years till February 2023, there had been 28 incidents involving the recovery of drones involved in arms and narcotics smuggling.Singh’s argument, therefore, is that while territorial security remains essential, it is no longer enough to define national securitySo, how should security be understood now?A key part of Singh’s address was his recognition of technology like drones and unmanned aerial vehicles (UAV) alongside disinformation campaigns as key challenges to the Indian security environment. The broader point can be loosely interpreted as that national security is increasingly viewed as the ability of the State and its economy to keep vital systems safe.Story continues below this adAlso Read | Rajnath says India didn’t use 1965 war’s ‘strategic advances’ to end infiltration: story of Pakistan’s Operation GibraltarAlong these lines, Singh also highlighted the importance of economic and energy security, with a focus on securing supply chains. India depends heavily on imported crude. Disruptions such as the effective closure of the Strait of Hormuz are, therefore, particularly consequential.Similarly, attacks on commercial shipping by the Houthis in Yemen have often forced vessels travelling between Asia and Europe to travel all the way around the Cape of Good Hope at the tip of South Africa. Such developments can undermine India’s energy security as the State and its consumers bear the costs of increased travel times, riskier insurance for merchant vessels and the need for a larger stockpile of crude to absorb future shocks.The same rationale also applies to critical technologies such as semiconductors and the supply chains propping them up.No State can, however, eliminate every vulnerability that might threaten its security across vast networks and industries. The question, therefore, is how to make an adversary conclude that the cost of an attack far outweighs the pay-off.Story continues below this adThis is where the concept of deterrence comes it. Deterrence means pre-emptively discouraging potential adversaries from engaging in hostile acts. This is generally achieved by indirectly or directly shaping the opposing parties’ perception of the costs they incur and the risk assumed.So, what does ‘deterrence by denial’ and ‘deterrence by punishment’ mean?“Our approach has evolved beyond deterrence by denial towards deterrence by punishment”, Singh said.Let’s According to RAND, an American policy research organisation, “deterrence by denial” operates on the logic that the aggressor shall not succeed because the defending State does not allow them to or successfully counter their actions.Story continues below this ad“Deterrence by punishment”, on the other hand, is similar to the concept of negative reinforcement in psychological conditioning. The logic is that a potential aggressor should realise that any hostile action would trigger a retaliation that would impose an unacceptable cost.In 2003, India’s Cabinet Committee on Security (CCS) adopted the ‘No-First Use’ strategic posture for the nation’s official nuclear doctrine. It specified, however, that nuclear retaliation to a first strike by another country would be “massive and designed to inflict unacceptable damage”.Also Read | India’s doctrine of Nuclear No First UseByond nuclear posture, India has largely followed a “denial by deterrence” mindset in the past, especially to manage cross-border terrorism.What might change about India’s approach to security?In 2017, the joint doctrine of the Indian Armed Forces formally integrated surgical strikes into its sub-conventional operations. It stated that conflict would be prevented by “punitive destruction, disruption and constraint in a nuclear environment”.Story continues below this adA year later, the 2018 Land Warfare Doctrine shifted the Army to a proactive approach, seeking to create operational space for punitive actions under the nuclear threshold using Integrated Battle Groups.The catch with the threat of punishment is that the potential aggressor must believe that the defender has the capability and mindset to carry out what has been threatened. The Defence Minister cited events such as the surgical strikes, the 2019 Balakot air strike and Operation Sindoor from 2025 to demonstrate that India has the capability and resolve to safeguard its national interests.So, when Singh says a terror attack originating from Pakistani soil will be treated as an “act of war”, he is signalling that India’s response may not necessarily be limited to addressing the immediate attack.