To try and prevent another world war from breaking out and obviously that didn't work.
While there was much buildup pre-World War I, it is commonly understood that the assassination of Archduke Franz Ferdinand on 28 June 1914 in Sarajevo pushed the world to war as a result of a complex web of treaties and diplomatic obligations that quickly were triggered and resulted in sides being chosen.
Because they wanted to make other countries go into war
B. it was in 1848, so that's before the civil war.