China joined 4 months after the US, so they probably shouldn't be listed as a neutral power.
Wasn't Portugal allied with Britain from the outset? hardly neutral at least
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But wouldn't Scandinavia also be harder to defend, with such a large coastline?
Norway wouldn't join the CP and the Baltic will become a CP lake.
I chose Spain because the idea of opening a second front in France seems pretty good. You have the French army being split in half trying to fight two fronts.
But given how near-disastrous the Italian invasion of the french alps in WWII was (at a point where France basically had already lost) I daresay France should be able to stall any Spanish advance at the Pyrenees.
Of course, needing some hundreds of thousand soldiers elsewhere might tip the scales towards the Central Powers, but then again Italy joining the Entente didn't topple the CP immediately either.
Afghanistan – received a German diplomatic mission trying to convince it to act against the British in India
Principality of Albania – In political chaos since the beginning of the war, the country was occupied by both Central and Allied powers but never declared war on either side
Ethiopia – received a German diplomatic mission trying to convince it to act against Italy, United Kingdom and France in East Africa
Venezuela – Supplied the Allies with oil
In reality, however, Norway had been pressured by the United Kingdom to hand over increasingly large parts of its massive merchant fleet to the UK at low rates, as well as to join the trade blockade against Germany. Norwegian merchant marine ships with Norwegian sailors were then required to sail under the British flag and risk being sunk by German submarines. Thus, many Norwegian sailors and ships were lost. Thereafter, the world ranking of the Norwegian merchant marine fell from fourth place to sixth place in the world.
The conspiracy was drawn up at the beginning of the war, with extensive support from the German Foreign Office, the German consulate in San Francisco, as well as some support from Ottoman Turkey and the Irish republican movement.