Now. We know the Elder Council is the main branch of government in the Empire. However, it was never really explained what they can or cannot do. So the point of this thread is to guess about the abilities of what the council can do. Though little is explained about that, a source did said that when a Septim Emperor was crowned, he was merely a figurehead with the only power in his reach is to veto any law. However, that wasn't the case for many of the Emperors. So it is most likely that their power changes through the course of the Empire's history.

Now I am going to focus on the Elder Council during the Mede dynasty, specifically, Titus II. All of the decisions he made in the Great war seemed to be made by himself with no Council involvment, such as refusing the initial Thalmor ultimatum, and signing the WGC. So it I would guess that Titus Mede had most, if not all, of the power and the Elder Council were merely a big group of advisers or pawns. (Perhaps this explains why the Council ordered a hit on Mede's head.)