Look at the trend of the 19th and 20th Century. Ever larger wars, involving more and more nations, and with technology improving at killing both the men fighting the wars and the civilians of any/all sides in ever increasing numbers. That trend of warfare and large scale genocide stopped after 1945. Because of atomics and later development of thermonuclears. Not because people and and nations decided to "give peace a chance". The pattern of routinely killing off entire segments of your own population and trying to kill everyone else on the other side of a particular border stopped because suddenly there was a weapon that scared both you and your enemy. A REAL terror weapon. A weapon that made people afraid to go to war, because it meant that no one would win. Nations without nukes would continue to bicker and those with would sometimes cheer on or support one side or another, but everyone knew that no one was crazy or suicidal enough to risk killing everyone. That was the last half of the 20th Century. Instead of real war where entire generations died, we had wars of paper cuts. But now there are players who may not be afraid of the genie, who aren't afraid of seeing the world burn, especially if they get to light the match. It's not the fault of the weapon. They are just a thing, a result of technology. They don't fear, they don't feel, they don't have an agenda, the people who develop or have them do. Just like guns don't create shootouts, their presence in the hands of a peaceful person discourages aggression from others, but will lead to bloodshed in the hands of someone who is eager or willing to spill blood for their own gain, nukes can be used to prevent wars, or to wage them. It all depends on who has their finger on the button.