User blog comment:Thedoucheinthenorth/The Civil War - Why it is great/@comment-76.172.16.254-20121120131249/@comment-1600847-20121120195503

There is no way of knowing whether or not he helped the Thalmor willingly. There's no doubt that during the events of Skyrim he hates the Thalmor, but before, who knows? Until we get more information, he may or may not have been their agent prior to the rebellion. There's not enough information to prove or disprove the theory. I personally doubt he's a Thalmor agent, but weirder things have happened in TES games before.

And I know I've stressed this point a lot, but a Stormcloak victory would militarily help the Thalmor. History has proved the saying: "United we stand, divided we fall" many times. It's much easier to conquer a nation that's divided and weakened from war than one that's been consolidating it's power. Do you really believe the Thalmor would face an equal challenge fighting a unified Empire versus an Empire that's lost Skyrim, and will therefore have less soldiers and resources and will have lost soldiers and resources fighting the Stormcloaks?