In my GB campaign I ended up annihilating the Iroquois and Cherokee first, whilst fending the Huron off turn-by turn in Rupert's land. At the point that I was ready to declare war on France, I was also ready to take the Huron great-lakes territory.
However, whenever I killed off the main Huron stack that was threatening Rupret's land, the 13 colonies would always drop a DoW on me in their next turn -this seemed to be independant of whether i was at war with France or not at the time too. I verified this through several reloads.
Ok, so I could still have blitzed the 13 cols, but i had geared up to take the French & spanish colonies instead.
So, holding off from destroying the Huron field army near the great-lakes/Rupert's land kept the 13 colonies on my side long enough to capture Quebec and ensure that they came over to my side without any fuss or bloodshed, as the mission promised.
I can only put this repeatable DoW from the 13 colonies down to scripted AI behaviour -presumably to stop the player being able to waltz through North America without as much of a struggle. It's annoying though as it hits you just as you think you are on the cusp of that pre-eminence in the theatre. Anyhow, I hope this helps those who faced it too!
Bookmarks