Congress serves two, not always compatible, purposes – representation and lawmaking. Members of the House and Senate serve individual districts or states, yet they are entrusted to act collectively to make laws for the nation as a whole. Collective action on divisive issues entails bargaining and compromise – among the members of each chamber, between the House and the Senate, and between Congress and the president. For compromise to be possible, members sometimes must retreat from their commitments to their individual states and districts. Determining who must compromise – and how to get them to do so – is the essence of legislative politics. The process can be messy, even distasteful, but, if it is to serve the nation, it is unavoidable.