The Structure of Leadership in Congress
US legislation is slow and at times painfully inefficient. In order to make new legislation, the Congress has to go through a long process of getting a majority in the house as well as the Senate, and even after all that the President still has to approve of the bill in question.
In the event that a minority party wins a majority of the seats in a congressional election, its minority leader usually becomes the majority leader. The minority party in the House also has a leadership structure, topped by the minority floor leader. Whoever fills this elected position serves as the chief spokesperson and legislative strategist for the party and often works hard to win the support of moderate members of the opposition on particular votes. Although the minority leader has little formal power, it is an important job, especially because whoever holds it conventionally takes over the speakership if control of the House changes hands.
The president should also have control and also listen to the counsel of family and friends. If these groups fail in any case, the Judiciary then takes up the matter and limit presidential powers to prevent imperialism.
Does this system encourage party loyalty above all else in members of Congress who want to get ahead? If that is the case, the impatience that Americans have with "partisan politics" is understandable.
Dye, Thomas. Politics In America, (8th ed.). New York: Pearson/Ph, 2009.
Smith, Steven, Jason, Roberts and Ryan, Vander Wielen. The American Congress (5th ed.). Cambridge: Cambridge University Press, 2007.