Party Size and Constituency Representation: Evidence from the 19th‐Century U.S. House of Representatives

Research on congressional parties assumes, but has not directly shown, that party size affects individual members' calculations. Drawing on a key case from the nineteenth‐century House—the secession‐driven Republican hegemony of 1861—this article explores the hypothesis that party voting not only declines but also becomes more strongly linked to constituency factors as relative party size increases. The analysis reveals that the jump in party size coincides with (1) a decrease in party voting among individual continuing members, (2) a strengthening association between some constituency factors and party voting, and (3) patterns of decline in individual party voting that are explained in part by constituency measures.