@Gargantua:
Well it’s a catch all rule then.
If for me to attack London I have to declare war Russia because there is a Russian Fighter there, the same rule would apply to a Russian Fighter on a British Aircraft Carrier, or Russian Ground units loaded in a british Transport. Or ground units in British Territory.
You also mean to tell me that if Russia drives into the Middle east early - because it is at war with Japan, and Russia parks its units in UK territory that I have to DOW on Russia to take these territories?
Which also leads me to conclude, if you use that same mindset you can’t attack Navies seperately at all if the two parties are at war with a major power. IE A russian Sub supports a british navy under attack. The same mentality saying if it was a fighter on the ground or on an ACC you have to declare war, wouldn’t it be the same for a sub or any other unit?
Personally I think that’s all garbage.
No, it has been firmly established that you can seperate naval battles if you’re not at war with one of the powers. If you’re at war with both, then you have to fight both. But you get to leave neutrals out in a seazone, and if russia leaves a plane on a carrier it’s not considered cargo during germany’s turn (planes are only cargo on the carrier’s owners turn, otherwise they’re “in the air”, which is why a sub can attack and even though the planes can’t hit the sub, they aren’t on the carrier when/if the carrier sinks).
Territories are different than seazones because you can control a territory, but seazones don’t belong to any power, so there can be other units in them (otherwise you wouldn’t be able to place units in a seazone adjacent if an enemy power’s navy was there).
Russian ground units on a british transport would be a bit of a conundrum. I’m certain never came up in playtesting, as loading friendly powers infantry as cargo is rare. I think they’d die, treated as cargo, and you wouldn’t need to declare war. Cause russia would be stupid to do it anyway, and I doubt a british transport would bother at any point before russia was at war with germany anyway.
But yes, ANY territory that has a unit of a power you’re not at war with requires a declaration to attack. Neutral units are NEVER displaced from a territory. If russia has a unit in a UK space, Germany MUST declare war on russia if they want to attack that UK territory.