We propose measuring group support for political parties by means of multivariate techniques that have become standard in other areas of political behavior. This approach yields improved insights into the marginal difference made by membership in each group and into the nature of a party's support coalition. As an example of this approach, we analyze the Democratic coalition since 1952. Our results differ from those of previous studies in a number of ways. Most significantly, differences with respect to the strength and timing of partisan changes lend support to Carmines and Stimson's conclusion that a realignment centering on race occurred in the mid-1960s. Our findings also indicate that the Democratic party is no longer so dependent on a few groups, as it was in the 1950s, but is now almost equally dependent on six groups.