Atomic bomb is a great deterrence, every sovereign nations should have it.

It is absurd to talk that every nation should possess the atomic bomb when the whole world is pushing for nuclear disarmament. The atomic bomb was detonated in 1945 during the great world war 2, the only country which had this capability was the United States, but now there are 10 countries which have accumulated around 15000 atomic bombs, which are thousands of time more stronger and devastating, so in actual the world is not moving for disarmament instead the nations are moving with great intensity of proliferation.
The world was in a multinational war since 1914 the starting of the world war 1, the war never ended in 1918 instead it progressed to world war 2, the actual end had arrived when the United States used the first atom bomb in the history of humanity, the whole world was shocked and felt devastated with the kind of destruction and human loss occurred. The attack brought the world on the negotiation table, thanks to the atom bomb, which had ended loop of war, started back in 1914.
There were several occasion when the world was on the verge of worldwide collision and all-out war scenario, but the wars were averted by knowing and calculating the risk of mass destruction, cold war, a war in Syria, North Korean aggression, Chinese aggression, Indo-Pak conflict, Yougoslovakia disintegration, gulf war, etc, these wars had the potential to spread and engulf the whole planet, but they were ended between two countries or with small escalation.
The consequences of a nuclear bomb attack are known to the leaders and people, any atomic explosion will lead to counter-attack, the bomb is now thousands of time more deadly, the impact could be the loss of atmosphere, radioactivity, and eventually the earth will become non-living.
Just imagine if the world had no atom bomb, cold war could have turned unprecedented conflict between USSR and US allies, India could have invaded Pakistan for 100 times for cross border terrorism, China could have been destabilized because of its radical system, which is against freedom, the United States could have invaded North Korea, China could have expanded more forcefully in south China and beyond, the world war could have happened during Syrian crisis, Ukrainian invasion could have happen by the Russian army, and all the wars which had confined to just proxy and escalated least, had the potential to widespread.
Although the war happened in the last 75 years, but if you calculate the human losses it would not exceed more than 5 million which is considerably nothing if you compare with losses during world war, the impact of having the atomic bomb could be clearly seen, the world is more interested in negotiation before conflict and resolves the difference without escalation. Thus, the atomic bomb plays important role in internal security.
The basic question is whether the nations around the world need to have right to have its own atomic bomb or not, the answer could be yes the capable and responsible nations should possess it, it will help the nations to defend its territorial and economic sovereignty of its own without any war, no other nation will try meddling in others internal affairs, the police state like US, Russia, France, UK and China had no work to do, they won’t be able to claim the responsibility of fake international security.