The document discusses several topics related to congressional incumbency: 1) Incumbency has become more of a career over time, with the proportion of first-term representatives falling from 58% in the 19th century to 8% by the 1960s. 2) Incumbents have advantages like name recognition, fundraising ability, and ability to perform constituent services, giving them a better chance of re-election. 3) Members of Congress can represent their constituents in different ways - as delegates by following voters' preferences, as trustees by following their own beliefs, or as partisans by prioritizing their political party. Most try to balance these approaches. 4) Congressional caucuses allow members