In presidential power and the modern presidents, richard neustadt identifies the source of a president's power to be

Explanation:

Key Point: "Presidential power is the power to persuade." (11) Presidents are expected to do much more than their authority allows them to do. Persuasion and bargaining are the means that presidents use to influence policy. Not only do presidents need to bargain to influence other branches of government (particularly Congress), but presidents also must bargain to influence the executive branch itself; cabinet secretaries, agency heads, and individual bureaucrats all have leverage that they can use against the president, requiring presidents to persuade even the executive branch, not merely command it.

Neustadt's conclusion is a good summary:

it further strained relations between the north and the south and convinced