Candidate Quality, the Personal Vote, and the Incumbency Advantage in Congress

This is a review of Candidate Quality, the Personal Vote, and the Incumbency Advantage in Congress (2007) by Jamie L. Carson, Erik J. Engstrom, and Jason M. Roberts. American Political Science Review 100 (May): 289-301. You can find the original in Google Scholar.

If democracy requires rotation in power, then the American Congress may not be all that democratic.

If democracy requires rotation in power, then the American Congress may not be all that democratic. In 1998, 2000, and 2002, over ninety-six percent of House incumbents who have sought reelection have won. These facts are clear.1

What is less clear is the source of this incumbency advantage. Previous research has suggested three answers. First, perhaps the perks of office, particularly the franking privilege and opportunities for casework, allow incumbents to endear themselves to their constitutions (Mayhew 1974; Fiorina 1977). Second, perhaps gerrymanding and weakened party loyalty are to blame (Erikson 1972). Or third, perhaps incumbents are so formidable that the best potential challengers simply refuse to invest their time running (Cox and Katz 1996; 2000).2

The trouble with these theories is that they have been developed and tested in the post-World War II context. Carson et al., by contrast, look to historical (1870-1900) House elections for further illumination. In so doing, they cast doubt on the first two theories, both of which claim that factors present today (but absent in the nineteenth century) cause the incumbency advantage. As it turns out, there was an incumbency advantage even then, even before members of Congress had large staffs (for casework), the frank, high salaries, and constant redistricting.

The authors then turn to the third theory. Cox and Katz supposed that their “scare-off” theory explained why the incumbency advantage had strengthened since 1964, the year of the Supreme Court’s “one man, one vote” ruling that led to perpetual redistricting. However, Carson et al. find 19th-century evidence of the same “scare-off” effect that Cox and Katz observed post-1964. Thus, although Cox and Katz may have identified a true effect, their “scare-off” effect cannot explain the recent rise in the incumbency advantage since the effect was present a century ago, long before “one man, one vote” took effect.

Candidate Quality in the Nineteenth Century

Much of the authors’ theory merely applies previous arguments from the literature. However, they do find themselves needing to defend one particular point. Late 19th century elections were much more party-centered than today’s candidate-centered affairs. With party leaders selecting Congressional candidates (rather than candidates openly competing in primaries) and with voters using party-printed tickets, should we even expect candidate quality to matter in this era?

Jacobson (1989, 787) argues that we should not. The reason lies in the competing incentives of parties and candidates. As for candidates, it is now accepted that Congressional election results depend crucially on challenger quality. When national partisan tides (and district-level concerns) favor an incumbent’s party, she is unlikely to attract a well-funded, experienced challenger (Jacobson and Kernell 1983). After all, potential challengers must bear costs to run–such as placing their political career at risk–so the best challengers will run only when success seems likely. The trouble is, however, that parties have the opposite incentives. When the national tide favors the Democrats, the Republican party wants to recruit the best possible challengers in an effort to forestall the pro-Democratic tide. In our candidate-centered era the party rarely gets its way, giving rise to the literature on challenger entry. But in the party-centered era that Carson et al. study, the criticism goes, we should not expect challengers to behave strategically; party leaders had pork, patronage, and other enticements that they could use to persuade high-quality challengers to run even against the partisan tide.

Carson et al. dismiss this concern, noting that self-interested politicians could refuse to run despite these incentives. Therefore, we should expect the same variations in challenger quality that we observe today–making the “scare-off” effect a reasonable thing to expect in the late nineteenth century. Moreover, candidate quality did matter, the authors claim; even though voters used party-printed ballots, the authors present anecdotal evidence to suggest that it was the Congressional candidate’s quality–not the presidential candidate’s–that influenced voters the most.

Empirical Evidence

The authors seek to predict the Democratic candidate’s vote share as a function of the lagged vote, the incumbent’s party (also lagged), a dummy for whether an incumbent was present (the primary coefficient of interest), and the Democratic quality advantage (a dummy indicating which party had the more experienced candidate; also lagged). They find that both incumbency and quality matter.

They then predict the Democratic quality advantage using essentially the same variables, and find that an incumbent’s presence lowers the likelihood of a quality challenger.

The Main Point

In case you missed it, here it is: Previous researchers have advanced three main arguments in an attempt to explain the origins of the incumbency advantage. But although their arguments may be true to an extent, they cannot be the full story. The first two theories depend on conditions that were not present in the nineteenth century, yet the incumbency advantage was–therefore, they cannot be the complete explanation. And the third theory claims to explain the increasing power of the incumbency advantage since the 1960s, yet it was present in the nineteenth century–so something else must account for the increasing advantage.

The main point: We still don’t know everything about what causes the incumbency advantage, so we need more research into it.

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