How did World War I affect European leaders' attitudes toward international aggression?

Good Morning!

With the first World War, not only the European countries but also the Americans and Asians, recognized the importance of maintaining alliances and the very high risks of local conflicts becoming world-wide.

The post-World War II attitude clearly illustrates the maturation of this idea, with the creation of the United Nations, with the aim of managing diplomatic and regional problems, preventing the development of crises of greater scales.

Hugs!