Legislative Professionalism and Incumbent Reelection: The Development of Institutional Boundaries

It is well established that legislators from highly professionalized bodies are more likely to win reelection than members of less professionalized legislatures. The authors of this article find that the effect of professionalization on incumbent electoral success is far more pervasive. As the level of professionalism of a legislature increases, members' relationships with the legislature's environment change: the effects of external political and economic forces (such as coattails from higher-level elections and national economic conditions) on a legislator's chances for reelection diminish in strength. This implies that legislative professionalization promotes institutionalization by establishing boundaries that insulate members from external shocks. The authors reach these conclusions by specifying and testing a district-level model of state legislative election outcomes having the probability that an incumbent will win reelection as a dependent variable. The model is estimated with probit using data for over 42,000 state legislators from 1970 to 1989.