Lets be honest who didnt kill Motiere? 

Ok what if the Thalmor invade Skyrim by crossing through Cyrodil where they would have both allies and enemies from the independent counts. Unbeknownst to them Ulfric is launching a invasion of his own into Cyrodil, and he too would have both allies and enemies from the counts. Ulfirc and the Thalmor then both meet on the feilds of Cyrodil.

Whats your thoughts?