I think the greatest argument in support of nuclear arms is that since their development, there hasn't been a war or even conflict between any of the world powers. That's almost 50 years of peace. That's unprecedented in world history. Are they justified? If using them leads to a quick, decisive victory over sacrificing the lives of millions of soldiers, yes. As terrible as they are, the loss of life inflicted by one or two nukes is small compared to the loss of life experienced in a total war scenario. Now, if their use led to nuclear retaliation and all out nuclear war, I don't think any conflict is worth that price. Better to be enslaved to a world power than to live in a dying world.