You know, now this is just a thought, but if you're not actually intending to fight you ought to make peace because all this continuation of an endless war does is galvanise the opinion in Aurvandil that the Veinsormoot will not accept peace by any means, by any concessions or agreement, and that leaves only violence as a resort.
Terran's demand that we pay them three thousand gold just to open up peace talks exacerbating what is now becoming a prevalent opinion in Aurvandil, and whilst Mendicant doesn't want to fight the Veinsormoot, nor even weaken them or to destroy any realm in the Veinsormoot, he won't be ruler for much longer if the Veinsormoot continues to spurn peace talks and he continues to refuse to launch military campaigns on the Veinsormoot.
If you're just going to uphold an endless war that you have no intention of either ending, or fighting, then Aurvandil is going to lash out because the current state of mass war is bad for internal affairs (Though, it has allowed Mendicant to get away with a lot of stuff that previously would have gotten him deposed, like Orthodox Astroism and Cult of Reason, or actually signing an alliance and with the Freestate no less) we don't want to keep fighting, and we don't want to be forced into a climate of constant hostility with our neighbours, which if they won't accept peace leaves their complete capitulation or destruction.