Grabbing for World Power: Germany 1914-1939
There is little debate that Germany started WW2 via Hitler, who in WW1, was just a lowly corporal in the trenches. Hitler's persona drove him to seek revenge and power upon the allied nations that stripped Germany after WW1 of pride in defeat. It is amazing to see how he rose to power with his political machine and how he used it for personal revenge beginning in 1939 with war in Poland.
What is often debated is how did WW1 began. Many historians state it was a series of events that made governments slip into war after the assassination of the Archduke of Austria-Hungary, the man to inherit the throne on June 28, 1914. He was murdered in Serbia, a foe of Austria-Hungary in the pre-war years.
But, research shows that Germany had decided on declaring war in Europe on Dec. 8, 1912, 18 months before. When the assassination occurred, Germany and its ally, Austria-Hungary, used the event to start it. But, Austria-Hungary also had sought to take the ruins of Turkey around Constantinople and the straits. So, when the assassination took place in Serbia, the Austrians were outraged and they sought to settle accounts (seek revenge). Austria an ultimatum designed to be rejected by Serbia (so Austria would have just reason to attack), but when Serbia actually agreed to the terms, Austria was dumbfounded. It did not last long, as they had decided to attack Serbia, even if this meant Russia might enter.
Before war began, there would be six meetings between all the European powers to resolve differences before WW1 started on Aug.4.
But, Germany and Austria-Hungary had already agreed to one thing-if Austria attacked Serbia, Germany would fully support them. This is important because Austria would not attack with Europe's dominant power supporting them. This agreement was reached on July 5th, a month before WW1 started. On July 8, the two countries reached a decision to attack Serbia even if a world war began. As the rumor of war grew louder, Russia mobilized its army on July 30. Like Austria-Hungary, Russia also wanted to seize the same Constantinople and Straits. after all, much of the Black Sea is in Russia. But Russia feared Germany as a regional power and was compelled and urged by France and England to "stand fast".
Because of a fear of Germany by England, France and Russia, it was natural for the nations to be on the same side. Germany and Austria-Hungary had prepared for conquest before WW1 began but lacked the will to start it. The assassination was the spark or excuse to begin the conquest by attacking Serbia. By attacking Serbia, the allied nations had to stand their ground and react accordingly.Germany's ambitions to conquer France were engaged and forced England to help France.
Unlike WW2, where Hitler turned east to conquer Russia, there was no such desire in WW1. The Russian front exploded out of fears. Russia reacted. Had the countries simply used diplomatic measures to punish and isolate Serbia for is actions, WW1 might not have happened, but it presented the opportunity to put plans into action for Germany and Austria. As for the USA, WW1 was of little interest from 1914-16, it was a "European war". But, America entered in 1917 and often saved the battle in 1918 because France and England were tired and suffered greatly, just as Germany had.
In the end, 10 million died by 1918, for this decision.