Question

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

Explanation:

The Constitution defines executive powers in a broad and unspecific way. This lack of precision leads to uncertainty about the limits of presidential power. Options A and D are more about how presidents act in different situations rather than the root - cause of uncertainty. Option B is incorrect as there haven't been major constitutional amendments that greatly increased presidential powers in a way that is the primary source of this uncertainty.

Answer:

C. The constitutional definition of executive powers is broad and unspecific.