The Atomic bomb has had one very big impact on most countries today, M.A.D.
No, not the movement about Mother disliking drunk driving, M.A.D. stands for Mutually Assured Destruction, what is that? Glad you asked. Mutually Assured Destruction means that if even ONE country fired a nuclear missile, then just about every other country would do the same, Mutually Assuring our Destruction. It stand to reason that this would happen because ALMOST every country has some form of alliance in the world with another country (thanks Switzerland, even during war everyone wants some chocolate and cheese from time to time). This leads to every country "backing up" every other country by "aiding" them with nukes fired at the opposing countries. This leads to the total annihilation of earth, and the majority of life on it, which is kind of something the human race should avoid. At this point though, the earth is at a general peace (albeit, things are stirring in North Korea), with various treaties to keep nuclear stockpiles down, and to limit the research and production of them.
Comic copyright to Bill Watterson