Ever since the recent military escalation between the nuclear powers of South Asia i.e. Pakistan and India, an ongoing debate at the domestic and international level can be witnessed about the deterrence factor and its applicability in such a critical situation. The situation begs the question as to whether the nuclear deterrence between the two countries had failed during this crisis situation. Or has it been instrumental in preventing further escalation and eventually an all-out nuclear war? In wake of Pulwama incident in Indian Occupied Kashmir (IOK) on 14th February 2019, India started blaming Pakistan for sponsoring the attack. As expected, after the incident India started threatening Pakistan for surgical strikes in form of a limited war. On 19th February 2019 Prime Minister Imran Khan offered India to have a joint investigation if India could provide any solid or actionable intelligence evidence of Pakistan’s involvement in the attacks, which India failed to provide. He also stated that Pakistan will ensure its territorial sovereignty at any cost and Pakistan will not just think of retaliation but will retaliate. On 26th February 2019 in the darkness of night India violated Line of Control (LoC) by sending jet planes. Pakistan Air Force (PAF) which was on high alert chased them immediately and compelled them to go back. The Indian jets released their payload in a forest of Jabba in Hazara region of Khyber Pakhtunkhwa (KPK) Pakistan while escaping. The 3-4 minutes violation of Pakistani airspace by Indian Air Force (IAF) was a challenge to the country’s sovereignty which Pakistan had to response to. The military official spokesperson Major General Asif Ghafoor said that now Pakistan will respond at the time and place of its choice, and that India should wait for the surprise. On the very next day i.e. 27th of February 2019, Pakistan retaliated by using its Air force, targeting military installations accurately across the Line of Control in Indian Occupied Kashmir (IOK). In response to this target engagement, IAF strike backed and during a dog fight PAF shot down two Indian jets and captured IAF pilot Wing Commander Abhinandan Varthaman alive. After this retaliation from Pakistan, international community which was reluctant to respond on Indian aggression feared further escalation that could eventually lead to an all-out nuclear war. In the South Asian context nuclear deterrence has been operational between Pakistan and India in critical situations like the 2001-02 military standoff and post-2008 Mumbai attacks, because of which the situation was kept from escalating further Coming back to the relevance of deterrence in the whole situation, broadly speaking, deterrence refers to a strategic policy adopted by states under which one state tries to dissuade (by employing the threat of use of nuclear weapons) the adversary by taking any aggressive action. In simple words it is a mutual threat of destruction via nuclear weapons. In the South Asian context nuclear deterrence has been operational between Pakistan and India in critical situations like the 2001-02 military standoff and post-2008 Mumbai attacks, because of which the situation was kept from escalating further. In the February 2019 situation India breached Pakistan’s sovereignty by violating airspace and was compelled to go back by PAF. But the question which occurred during this entire episode was the applicability of nuclear deterrence. The airspace violation by India is a conventional form of war fare which was conventionally responded by Pakistan the very next day and evidence was shown to the world. The international media questioned India about the evidence of the ‘claimed’ surgical strike, which India failed to provide at any operational or strategic level. After the successful strike back from Pakistan which the country has reserved the right to do so, it was feared that the situation will further escalate politically, militarily and might turn into a nuclear war. At that stage the existence of deterrence worked out from Pakistan’s perspective and from the international perspective. India was humiliated with Pakistan’s retaliation and the questions were raised all around the world including India about the credibility of surgical strike. After the shooting down of two Indian jets by PAF and arrest of Wing Commander Abhinandan international community feared that India will go for a limited war against Pakistan under its ‘Cold Start Doctrine’ (CSD). Pakistan’s tactical nuclear ‘NASR’ having shortest range of 60-70 kilometers proved to be a deterrent in that scenario which Pakistan re-tested on 31st January 2019 successfully. India and the international community had an understanding that any further escalation may lead to a nuclear exchange because Pakistan will be left with no choice but to use its tactical nuclear weapons. Pakistan’s India centric deterrence trajectory over the years has evolved from ‘minimum credible deterrence’ to ‘full spectrum deterrence’ because of Indian ambitions to find a ground for conventional war. This posture provides deterrence against all forms of aggression (from India) with the combination of conventional forces and nuclear capabilities. In February 2019 episode India’s conventional capabilities were met by Pakistan’s conventional capabilities thus formulating an ‘appropriate response’. The deterrence factor remained applicable in the whole situation even without using the nuclear weapons. The recent standoff between Pakistan and India is one of the worst crises; it could have resulted into an all-out nuclear war. The possession of nuclear weapons by Pakistan prevented it to further escalate otherwise conventionally India has edge in terms of quantity of military hardware. Pakistan’s full-spectrum deterrence assured the perception of ‘massive retaliation’ in Indian politico-security hierarchy. The Indian conventional misadventure is conventionally retaliated by Pakistan and proved to be politico-military success. The nuclear capability of Pakistan is a ‘weapon of deterrence’ and a ‘political choice’ as well. The writer is working as a Research Associate at Strategic Vision Institute (SVI) Islamabad