Board Thread:General Discussion/@comment-50.72.53.15-20131217031236/@comment-24261859-20140114083431

Divided, the former Imperial provinces stand no chance. United, they could pose a decent threat to the Dominion, especially on the defense. Perhaps they can't take Alinor, but they could liberate the mainland and do decent damage to the Thalmor holdings in Elsewyr and Valenwood. Once the Empire goes to war against Alinor, skyrim will undoubtedly join in even if Ulfric won the Civil War--even if it is a temporary alliance, do you honestly expect that he would pass up a chance to take his revenge against the Dominion? You then have Cyrodill, High Rock, Skyrim, and likely Hammerfell working together. The orcs may join in as well given their connection to High Rock and ties to the Empire.

So, as 74.186 said, you have the three most powerful warrior peoples in Tamriel bonded together, with some competent (if not quite as much so as Altmer) magic users too.

Black Marsh will likely stay neutral, as will Morrowind. I doubt the dunmer have any love for the Dominion, but what with their homeland ravaged by the Red Mountain's eruption and not particurlarly great relationship with Cyrodill, I do not expect them to actively participate in the Great War.