Sanctions were originally conceived as a way to keep peace on the european continent, and they did work to prevent war between smaller countries. But when used in the wake of the great depression, they ended up actually accelerating political and economic disintegration in the world. Sanctions affect everybody right away, equally, because everybody starves together. Seven year old who wouldn't go out on to the battlefield is going to starve along with the 21 year old who would. The real tragedy of the 19 30s is that sanctions had worked in the previous decade, but precisely when they were used in the following decade it turned out not to be so effective.