Oh please, America, Germany, and Japan pursued the development of nuclear weapons in World War II. It was America that beat the two nations in the nuclear arms race during the war by successfully developing such weapons before them. America had the money and power and upper advantage to produce the most awesome weapons that the Axis powers failed and thus managed to be the first one to use it twice against a fanatical enemy in the middle of a world war. If it weren't for America developing or using such weaponry, then some other country would have developed and used it in order to show the world the display of nuclear power on a target anyways.
Nuclear weapons are mainly the reason why wars are limited to proxy or limited wars instead of all out non-nuclear wars between two or more major powers like Russia, Germany, UK, France, U.S., and Japan. It's strange to think that way, but that's pretty much how it is. Only we need to worry is preventing bad actors or states from developing and deploying nuclear weapons against a target in a technology and doctrine that has vastly improved over the decades.