One of the LARGEST non-nuclear detonations ever, was the infamous "Black Tom Explosion" in New York harbor in 1916. This explosion was so huge it not only destroyed a ship and a large munitions plant, but actually damaged the Statue of Liberty...something like a half-mile away. At the time, Americans were told it was an accident, but, the government knew (and revealed in the 1920s) with clear evidence that it was an act of German sabotage. Along with Black Tom, apparently over 50 acts of German sabotage were known during the war.
The fact of the matter was that the US government, and US corporations, were actively supporting the Allies from the very beginning of the war. Munitions manufacturers made tens of millions selling to the Allies, and Wilson, in spite of his promises to keep the US out of war, was actively looking for a pretext to get involved...so it really is no wonder that Germany saw the USA as its enemy long before we entered the war openly in 1917.
Once again, I wish we had stayed out...but we didn't, and since we were involved in WWI all along, given German sabotage, especially after the enormous Black Tom Explosion, no wonder Wilson was incredibly anti-German...even to the point of opening internment camps.
I suspect that if the US had stayed out of The Great War, Germany may very well have won, and a certain Austrian painter would have died in anonymity.
By the time the Germans launched their Spring Offensive in 1918, they were nearly dead, but the French were in even worse condition, and the Germans probably would have taken Paris if not stopped by the Americans at Belleau Wood.
The Nazis didn’t take power from a broken Germany. The Weimar Republic caused inflation (printing money rather than cutting government or raising taxes) and ended it before the Nazis took power. During the time of high inflation Germany was not terribly poor, and in fact was rather prosperous as its monetary inflation made its products very attractive to foreign nations.