Seeing as how the Imperials gave away red guard land to the Thalmor and the redguard fought a bitter war and whoop the Thalmors ass with no help from the Empire, which gave the Nords the ideal that they're not unbeatable. If only the empire stay out like they did in Hammerfell... The Redguard and the Empire don't see eye-to-eye right now. Again, If the empire would let the nords alone, they could get an army back in cyrodiil and prepare to face the thalmor once more. Meanwhile, the stormcloaks could do the same. The thalmor did not even managed to capture hammerfell, and it's a fricking desert with a nomad populace. The nords are a very strong race and could defend themself very well against the aldmeri dominion. Then after the thalmor is beaten, the empire and the stormcloaks could start peaceful negotiation to welcome the nords once more amongst the empire. The skyrim war is simply a tiring war between two faction with a slight opinion disagreement, that's why the thalmor intended to save ulfric. Because they knew that if the war would go on, both the nords and the empire would be too weak to resist another assault from them. And for you'se siding with the empire, your strings are being pulled by the Thalmor. Hello, patsies!!!