The United States of America declares war on Imperial Germany.

Here's an interesting "What if" article: "Should America Have Entered WWI?" https://nytimes.com/2017/04/06/opinion/should-america-have-entered-world-war-i.html

Basically, the author argues that without the impending arrival of 1.5 million fresh American troops, England and France, in the face of increasing war exhaustion, would eventually not have been able to continue to carry out the war, and Germany would not have launched (also faced with the prospect of impending war exhaustion) a last-ditch Spring 1918 offensive, which, of course, hastened the eventual collapse of the German army.

No Treaty of Versailles, no humiliating war reparations, no eventual rise of Hitler -- at least that is the argument. Also, although the article doesn't raise the question, without the arrival of the Americans and the eventual collapse of the German armed forces, would Kaiser Wilhelm have had to have abdicated? Eventually, the whole thing might have started all over again, with or without Hitler.

"Triumph" of Hitler and the Nazis? He must have a different history book than I.


Why arbitrarily select and blame the arrival of US soldiers in WW1 for WW2? His same theory would hold had there not been a WW1 in the first place. In any event, if my aunt had balls, she'd be my uncle...

Why wouldn't Germany have launched an offensive in 1918?

After Russia was beaten by Germany and her allies in 1917 (the US had no role to play in that), it freed up large numbers of German divisions that would have been used against France and Britain in any case. The American involvement simply hastened the German plans and made them more desperate. But the German economy was already being strangled by the British blockade and their civilian population was starving from lack of food supplies. Germany would have gained nothing by waiting it out in 1918. Time was against them, and not only in the form of the crippling Allied blockade, but also with the internal troubles threatening Austria-Hungary and the Ottoman Empire, Germany's most important allies.

So I'm convinced that there would have been a German offensive in the west in 1918, even without open American involvement in the war. The only way Germany could win in 1918 was to decisively smash France and hope that would be enough to push the British into the negotiating table.

The authors comments are all very interesting but Hypothesis. It's the "What if" scenario which is only valid if it bears fruit and of course it never can when one is looking back at history. C'est la vie!

It is plausible that the entry of the US to the war motivated the Germans to allow Lenin free passage to Russia, in the hope that he would cause trouble and hamper the Russian war effort. Whether or not this was the case, Lenin certainly did some hampering. Of course, it would be ludicrous to pin any responsibility for this sequence of events upon the US. Even the Germans could have had no idea they were about to open the gates of hell upon the Russian people.

I'm thinking if US doesn't enter the war, Germans don't initiate the Amerika program and they lose the war even faster. And Mexico attacks America and steals Texas.
In 1941 Japanese attack Acapulco and not Pearl.

Couple days ago I was thinking about this sort of butterfly effect. Obviously this is far-fetched, but interesting nonetheless.

I was thinking, what if the chauffeur of the Archduke's car would have been informed about the change of route. Or maybe he was but didn't pay attention. Then he wouldn't have turned into the wrong street how initially planned. Then he wouldn't have stopped to make a turn, coincidentally right next to Gavrilo Princip, when realizing his wrong route. Then the Archduke wouldn't have been assassinated (since all other assassins failed badly).
If that wouldn't have happened, then Austria-Hungary didn't have to make an ultimatum with such harsh demands which Serbia could not accept.
Then Germany wouldn't have been so cocky to give Austria-Hungary such a Blanco-Cheque.
Then maybe Austria-Hungary wouldn't have declared war on Serbia. Maybe they would for some other reason, since Serbia was a PITA for them, but maybe on a smaller scale without the backup of Germany.
Then the whole machinery wouldn't have started. (Russia wouldn't come to Serbias aid, Germany wouldn't have to declare war on France and Russia. There wouldn't be a need for the Schlieffen plan to go through neutral Belgium, which triggered the involvement of the UK etc.)
Then there would be maybe a smallish war in the Balkans, but no Great war.
Then Germany wouldn't be treatet as the lone aggressor, which humiliated them.
Then the monarchy in Germany would maybe still be here today, like in the UK etc.
That means no Weimar republic, no fights between bolshevics, nationalists, monarchists etc.
No Lenin unleashed in Russia, still monarchy probably.
Hitler would have stayed a bum in Austria instead of fighting for the German army, becoming a German citizen.
No stab in the back myth, no rise of nationalists. No humiliated German nation where many were thankful for such a "strong and loud leader", who gave them promises and sort of pride back (look at Turkey today, this small Sultan there is about doing the very same). No enemy image of Jews or Bolshevics, at least not at this scale. Rather a not so nationalistic state as it was before the Great war.
The arab countries wouldn't have been divided by the allies into nations with pencil and ruler. No such inferiority complex as you can see nowadays, or maybe not at this scale.
The Windsors would still carry their original German name.

Later on maybe no Hitler, no Stalin (because of no Lenin before).
No cold war, No Vietnam war, no Korean war, therefore no Northkorea, no communist Cuba, no Eastern Germany etc.
Also this means no Atomic bomb, no such a fast progress with rocket science, Wernher von Braun would stay in Germany, maybe the first moonlanding would have been about today.
America wouldn't have been what it is today, because their rise in all regards has begun after WW1.

Probably all this would turn out about the same, because of other reasons, who knows. But still, even if far-fetched, an interesting thought, that maybe a chauffeur was reading a comicstrip in the newspaper, while the change of route was announced, so he missed it, and that triggered all these events. How a small, unimportant moment can change the world completely for centuries.