I was recently reading about WW1 and came to a realization: in more ways than one, WW2 was the second chance for not only Germany, but also countless of her WW1 allies, to achieve what they almost did in WW1.
Just prior to WW1, Germany organized a series of powers into what came to be called the Central Powers. They were aided by the elite in Austria-Hungary (including the elite in its composite nations, Moravia, Bohemia, Slovakia, Croatia, Bosnia), Bulgaria, and also Turkey. Italy was allied with Germany and Austria-Hungary prior to 1914, but then stabbed Austria in the back once the war started, and joined the Allies. Also of interest is that Romania's king (Romania had the highest oil reserves in Europe outside of Russia) had an alliance with Germany and Austria, but when he died in 1914, his son had the kingdom switch sides and join the Allies.
Many serious scholars believe that Wilhelmine Germany (the name we give to Imperial Germany under the Kaiser) came closer to winning WW1 than WW2, and this is one of the reasons why WW2 was fought. In a sense, the popular belief was that if they came "that close" in 1914-1919, they might as well give it another try.
In WW1 the Germans succeeded in beating Russia. They forced the Russians to cede Ukraine, Belarus, the Crimea, all of Poland, Lithuania, Latvia, Estonia and Finland. The Germans established puppet governments and then turned to the West, where they hoped to win the final knockout blow. What happened was that their offensives failed, and even though the Allies failed to invade Germany (and Germany still occupied large sections of France, Belgium and enormous parts of Czarist Russia), Germany's population started to revolt, due to food shortages and mutiny among soldiers and sailors who refused to throw their lives away.
What's interesting is that the same basic bunch who supported Germany in WW1 are the ones who joined her in WW2.
Hitler, not wanting to repeat the Central Powers' mistake of losing Italy and Romania to the Allies (as in 1914) went to great lengths to bring these nations onto the side of the Axis in 1940. The Austrians, Hungarians, Slovaks, Croats and Bulgarians, although now independent, still joined up again with Germany to fight another war.
Hitler was convinced that the Kaiser was silly for having let the Japanese enter into an alliance with the British against Russia (after 1905) as this was later used against Germany. As such, he put great emphasis on bringing Japan out of the British orbit and enlisting their support for a general war against Russia in general and Communism in particular.
Not wanting to once again get into protracted trench warfare in the West, too, is what propelled the Nazis to focus so much on the development of Blitzkrieg.
It's interesting to look at this time period and see how much what was considered by the Germans in the 1930s was informed by their failures in 1914-1918.
In this sense, although the genocides and Holocaust of WW2 were the sole brainchild of Hitler, the Nazis and like-minded fascists, the same cannot be said about German continental imperial ambition in general. I think it's fair to say that the "deep state" in Germany---those old generals and retired military folks who were children under Bismarck, served under both Kaisers and comprised the elderly bureaucratic and corporate elite of Germany in the mid 1930s----had always wanted to have a "second chance" at waging global war and that Hitler merely gave them the opportunity they were looking for. So much of it seems to be following the same playbook. The same countries targeted for the same reasons in both wars. The smost obvious mistakes in WW1 consciously being rectified just prior to ww2. The same foreign elites co-opted for the same reasons. The same industries lobbying for access to resources in the same occupied territories.
The interesting thing is that, despite everything that Hitler did to try and avoid the mistakes made by the Kaiser, he still lost the war. I believe, based on my readings, that this came about primarily because of the alliance with Japan, which drew Germany into a war with the United States. Evidence clearly shows that Germany did not want to draw the US into the war until or unless the Russians had already surrendered. And they wanted the Japanese to invade Russia from the East. 1905's Russo-Japanese war showed that Russia was simply to vast for any government---whether Czarist or Communist----to wage war on two fronts simultaneously. The curious thing is that the Germans declared war on the US out of an obligation to Japan, hoping the Japanese would live up to their promises and declare war on the Russians. This never happened. And that, I think, after careful analysis is where the war was ultimately won by the Allies.
Had the US not entered the war, and had Japan followed through with her alliance obligations with Germany, the Axis would have won. Once Russia fell, then each Axis power would have been able to fight a one-front war against the Allies.
This realization, more than anything else, should make us realize just how important global alliances are to the survival of democracy. Our current democratic world order is far more fragile than most people appreciate. There is nothing pre-determined about the dominance of Western democracy.