For them to take it over they will need a large force, like I said. Which I highly doubt they will risk of doing it. Also how can the Empire hold off the Thalmor by itself? It only has three provinces itself. It has half (or even more) of it original strength gone due to the treaty is slim. Plus if war happens again, then the Thalmor already have a foot hold in Empire, I don't doubt they have forts within the Empire since they have it in Skyrim already.The Bum said:snip
Plus at least within Skyrim it will be harsh. Due to the weather, dragons, and very far from thalmor homelands. It will take a lot of supplies to reach back and forth between thalmor homeland to Skyrim.
Which leaves a few options of them entering. Through the boarder between Empire and Skyrim which can easily protected since Skyrim is heavily mountainous place. The other is by boat so that could lead to some problems for both sides. If the Nords can put enough defense along the coastline (Which it seem that even by boat might be a problem since we seen a ton of boats shipwreck) they can hold them off.
To the point of the Empire helping the Thalmor I suggest you look at the Grey-manes' son. Who was mysteriously taken away. When you learn more about it, you learn the Thalmor taken him. How did they do this? Also why? It doesn't seem like the Thalmor were anywhere near Whiterun. So someone must have kidnap and handed him over.
On the last two points, if you are fine with civlains who get kidnap from their homes and torture and killed for just being declare "Talos worshipers" just remember, the Thalmor can do this to ANYONE. Even if they were not part of it. How would you feel if someone close to you got taken away in the middle of the night. Would you be piss off and try to stop them? or just say "Well its for the good of the Empire carry on."
The last thing, the stormcloaks are not all racist or nationalist. They are very very xenophobic and magicphobic. Within good reason but it still doesn't excuse their behavior. With the whole Xenophobic just take a look at all the other racist have cause. High Elves, the great war, Dark elves use to kidnap Argoians as slaves and etc, and now Black Marsh has invaded Morrowind and doing the same thing now to the Dark elves. The whole world is going to hell pretty much. Neighbors are getting drag out of their houses by the Thalmor.
Wouldn't that put a huge trust issue you see from the other racist? Sure they are a very proud race of warriors. Though you also have to see, Skyrim is their home and is mostly populated by Nords. Does it make it right? No, but they feel like they are the only ones who give a damn about their own country.
It still doesn't excuse their behavior but that's my intake on why they are acting like this. Also at least they don't do public execution and drop their allies when they are losing a fight. If the Empire would stay in fighting the Thalmor in the first war, they could have won. They will still have their major provinces behind their backs to win the war.
All they have now is just Skyrim, High Rock, and Cyrodiil. Not looking to great on the Empire end. One more thing, look at a map of Elder Scrolls. The Thalmor are right behind the Empire and have easy access to attacks. While in Skyrim they have to travel quite a bit to even reach it.