Most people, when put under prohibition, will become desperate for the drugs once they are deprived of it and then they will use these drugs illegally. This in turn will increase the crime rate. This didn't work in the 1920s and it isn't working very well today, but that doesnt mean that there are good things about prohibition either. Alcohol and marijuana lead to bad choices made by the user and eventually death. So if using alcohol and marijuana alot is more important than life, then go ahead and use them.
WW1 was a tough war to win and the casualties were very high. It's foolish of everyone in the world to continue to go to war. What is the gain? Death?
Trench warfare is one of the most brutal fighting tactics out there. Not just the fighting either, the living as well.