Since 2014, the United Nations has been annually observing the International Day for the Total Elimination of Nuclear Weapons. The decision to observe such a day was taken when the 2013 United Nations General Assembly (UNGA) passed the resolution 68\/32, which called for the \u201curgent commencement of negotiations in the Conference on Disarmament of a comprehensive convention on nuclear weapons to prohibit their possession, development, production, acquisition, testing, stockpiling, transfer and use or threat of use, and to provide for their destruction\u201d. The decision to commemorate September 26 as this day every year was passed by the UNGA resolution 69\/58 in 2014, and since then this day is observed to make people aware across the globe about the threats posed by nuclear weapons and nuclear proliferation. Since the US dropped atomic bombs on Hiroshima and Nagasaki during the Second World War, the international order has fundamentally changed. The potency of this weapon encouraged great powers like the erstwhile USSR to join the nuclear arms race, thereby increasing their nuclear stockpiles manifold. The great debate has been always about whether the world needs nuclear weapons or not? The answer to this question can\u2019t be in black and white, because while the threats of nuclear weapons are immense, the deterring nature of these weapons provides a security guarantee to many states\u2014a point reiterated by the proponents of nuclear weapons. Scholars and experts on nuclear disarmament have been divided on the question of whether the spread of nuclear weapons is a good thing or not? For example, Kenneth Waltz, who is recognised as the father of realism in international relations, had a classic debate with another scholar Scott Sagan on the very issue where these two took opposing views. While Waltz argued that the consequences of nuclear proliferation are likely to be positive, Sagan opined they are likely to be negative. Waltz, in his analysis, took the stand for nuclear proliferation, and Sagan argued that considering the destructive nature of such weapons, proliferation would prove extremely costly to nation states and the world at large. Historically, it has been observed that when a nation state possesses nuclear weapons, it is less likely to go to a full scale war with another state. The reason being that these weapons have the capability to annihilate entire populations and the radioactive residue left behind leads to hazardous health consequences on future generations as well. As a result, no nation state takes the risk of going to a war with a nuclear weapon state. For instance, till the time North Korea didn\u2019t declare itself as a nuclear power, the tensions between it and the US (and its allies) were escalating to dangerous levels, and many thought it could lead to a full blown crisis. Once the Kim Jong-un regime declared its nuclear arsenal, the US took a different approach, with President Donald Trump meeting Kim Jong-un in Singapore in June 2018. One of the reasons could be that the US understood it couldn\u2019t deal with North Korea as it did with Saddam Hussein\u2019s Iraq or the Muammar Gaddafi regime in Libya, who did not have the power of deterrence that comes with nuclear weapons. Interestingly, the power of a nuclear weapon state actually lies in not using the weapon, but in having it\u2014because once a state uses such weapons, it can risk the wrath of the entire international community. Nuclear weapons, thus, aren\u2019t weapons for offence, but for deterrence. Even their usage for defence might be justified only when a state faces the gravest threat to its security and survival. Such weapons put conventional military strength out of question, and reduce the power gap between nation states. For example, India is far ahead of Pakistan when compared in terms of conventional armed forces strength. But since both are nuclear weapons states, it is unrealistic for them to go on a full scale war with each other. The biggest threat today about nuclear weapons is the fear of these going into the hands of non-state actors, like terrorist groups, who can exploit them, inflicting tremendous harm to the humanity at large. The debate between the feasibility of nuclear weapons and nuclear non-proliferation will go on, but the important thing that responsible nation states should keep in mind is that these weapons should not go into irresponsible hands that can put the global security at a great risk. By Martand Jha, Junior research fellow at the School of International Studies, JNU.