How did the network of European alliances call world war one to develop

The alliances said they had to fight for each other in war

Explanation:

The alliances system meant that a local conflict could easily result into an intimidating global one. The overall cause of World War was the assassination of Archduke Franz Ferdinand. Nationalism was a great cause of World War one because of countries being greedy and not negotiating.

lincoln declared that slavery should not be allowed to spread into the new states, and of course this angered the south at the time.