Thats right... Well in that case did you really expect Carelia to pursue war with Suville gaining another ally? Then again with Tara helping us I believe you would be kinda irrelevant as we would just make sure the Tarans disabled you from helping by always having atleast one Taran with us.
Actually that decision would have depended mostly on Asleon's recommendations on who was 'right' in your conflict and who wished to continue war.
I'm curious though you intend to go to war again, but not Suville. There are only 2 options left really:
1] Attack the central alliance (unless you get Tara's help that's gonna be a death sentence)
2] You can join in on the assaults on Eston/Darka, but I'm not sure if that little bit of extra aid at this point will do anything than possibly slightly speed up the process.
Although you could always continue the Redspann way, go and march to BoM! After all, you do occupy some of their former lands.