What is the primary source of uncertainty over the limits on presidential power? some presidents win their elections by greater margins than others. constitutional amendments have greatly increased presidential powers. the constitutional definition of executive powers is broad and unspecific. some presidents increase power in times of need.

The primary source of uncertainty over the limits on presidential power is that the constitutional definition of executive powers is broad and unspecific. The founders meant for this to be the case because they knew that in certain times of need, the president will need to take drastic measures to remedy certain issues, like Lincoln during the Civil War.