Members of Congress, once elected, are likely to be reelected. Members of Congress can use their office to publicize themselves, pursue a "service strategy" of responding to the needs of individual constituents, and secure pork barrel projects for their state or district. House members gain a greater advantage from these activities than do senators, whose larger constituencies make it harder for them to build close personal relations with voters and whose office is more likely to attract a strong challenger. Incumbency does have some disadvantages. Members of Congress must take positions on controversial issues, may blunder into a political scandal or indiscretion, must deal with changes in the electorate, or may face strong challengers. Any of these conditions can reduce their re-election chances. By and large, however, the advantages of incumbency outweigh the disadvantages, particularly for House members. Incumbents' advantages extend into their re-election campaigns. Their influential positions in Congress make it easier for them to raise campaign funds.
Congress is a fragmented institution. It has no single leader; the House and Senate have separate leaders, neither of whom can presume to speak for the other chamber. The principal party leaders of Congress are the Speaker of the House and the Senate majority leader. They share leadership power with committee and subcommittee chairpersons, who have influence on the policy decisions of their committee or subcommittee.
It is in committees that most of the day-to-day work of Congress is conducted. Each standing committee of the House and Senate has jurisdiction over congressional policy in a particular area (such as agriculture or foreign relations), as does each of its subcommittees. In most cases, the full House and Senate accept committee recommendations about passage of bills, although amendments to bills are quite common and committees are careful to take other members of Congress into account when making legislative decisions. Congress is a legislative system in which influence is widely dispersed, an arrangement that suits the power and re-election needs of its individual members. However, partisanship is a strong and binding force in Congress. It is the basis for party leaders' ability to build support for major legislative initiatives. On this type of legislation, rather than committees, the party leaders and caucuses are the central actors.
The major function of Congress is to enact legislation. Yet the role it plays in developing legislation depends on the type of policy involved. Because of its divided chambers, weak leadership and committee structure as well as the concern of its members with state and district interests, Congress only occasionally takes the lead on broad national issues. Congress normally looks to the president for this leadership; nevertheless, presidential initiatives are passed by Congress only if they meet its members' expectations and usually only after a lengthy process of compromise and negotiation. Congress is more adept at handling legislation dealing with problems of narrow interest. Legislation of this sort is decided mainly in congressional committees where interested legislators, bureaucrats, and groups concentrate their efforts on issues of mutual concern.
A second function of Congress is the representation of various interests. Members of Congress are highly sensitive to the state or district they depend upon for re-election. Members of Congress do respond to overriding national interests but for most of them, local concerns generally come first. National and local representation often work through party representation, particularly on issues that divide the Democratic and Republican parties and their constituent groups.
Congress's third function is oversight, which involves the supervision and investigation of the way the bureaucracy is implementing legislatively mandated programs. Although oversight is a difficult process, it is an important means of control over the actions of the executive branch.