@WILD:
Ok we have a difference of opinion here. I say Russia is not officially at war until it can declare it on its own turn. I reread the “Powers That Begin The Game Neutral” side bar on page 15. It doesn’t spell out that if you are attacked you are automatically at war. It does say that if your not yet at war, and you now have no restrictions (Germany attacking you would remove all restrictions) you may declare war at the beginning of your turn (before combat movement). It would be the same if Japan did an unproved attack on the UK. The US is not automatically at war w/Japan. It still has the option of declaring war or not when its turn rolls around (it will normally do a DOW its a no brainier). I’ve not been in a situation in Pac40 (that I can remember) when the US or UK had a war ship in a Jap convoy zone (and would still be there in Jap collect income phase) when Jap did DOW and made a direct attack on one or both of them. So it hasn’t come up in our group yet. I do vaguely remember Krieghund clarifying something similar before.
I think Krieghund needs to clarify now, I have been wrong in the past, but that is how I saw it.
I could also be wrong, but I’m 95% certain that this is the case as I was just reading through the errata thread last week and I think I read all this again. If Germany declares war on Russia, a state of war exists between them and all Russian units are hostile. A Russian warship would be able to disrupt Germany’s income on the turn that Germany declared war because it has a ship belonging to a power with which Germany is at war. Russia doesn’t need to declare war, as I think the rule is written such that your income is disrupted by a power with which you are at war and specifically not written such that your income is disrupted only by a power that has declared war on you. Once one power starts the war, retaliation is immediate as far as convoys go.
In Pacific, it is possible for Japan to declare war (unprovoked) on the UK and not the US, attack a seazone containing both nations’ ships, engage and destroy only the UK ships, and be safe from convoy disruption by the US as it is not at war with the US. The US is now free to declare war on its own turn, and would then be vulnerable to convoy disruption by Japan on US’s turn (again, because if a ship belonging to Japan, a power with which it is at war, is present in US convoy zone, regardless of which power declared war, it will disrupt income). Germany can do the same by remaining neutral to the US, engaging only UK units in a seazone containing US & UK ships, but the US could not retaliate in any way at all on their turn as that attack does not incite them.
Once war has been declared by one side, declaring war on the other side is a formality. I believe by a strict reading of the rules Russia is required to declare war in order to make combat movements against Germany and noncombat air travel over German spaces, but the German units are already hostile, and Russian Convoy zones would be vulnerable (if there were any) because a state of war already exists between them. Russia could not, for example, noncombat move through a seazone containing German warships after Germany declared war, even if Russia chose not to declare war in response on their turn.