In terms of sheer size, the most important religious group in the United States is the Catholic population, with 51 million identifiers. This potential voting bloc has undergone dynamic change in recent decades in its pattern of party preferences. The difference in party preferences between members, or practicing Catholics (who both identify with the church and participate in parish life), as against "cultural Catholics" (who self-identify as Catholic but do not say they are currently "members") is quite striking, especially once the Hispanic Catholics, who now comprise one-third of the nation's Catholics, are separated out.

Among the registered voters, non-Hispanic practicing Catholics favor the Republicans over the Democrats by thirteen points (41 percent to 28 percent, Figure 8), but among the cultural non-Hispanic Catholic voters this is reversed, and the Democrats are favored over the Republicans by eight points (36 percent to 28 percent, Figure 9). Even among the Hispanics, who are largely an urban and lower-income population, the practicing versus cultural Catholic political divide also occurs. Practicing Catholic Hispanics favor the Republicans by eight points and are fifteen points less likely to support the Democrats than Hispanic, cultural Catholic voters.

The current context of polarized public religious discourse has obviously rent apart the long-established non-Hispanic Catholic community. (The number of nonwhite non-Hispanics, mainly Asians and blacks, is insignificant as a proportion of this population.) The emergence of this population of cultural Catholics reflects the vestige of eroded connections to upbringing, family, or ethnic community. The cultural Catholics who identify but don't affiliate are the wild card in any assessment of the role of Catholicism in contemporary American politics. In fact, ARIS is the first empirical study to offer the opportunity to measure the consequences for voting among the nation's largest religious tradition of this growing division between cultural and practicing Catholics.

The fact that practicing Catholics are now so Republican in party orientation shows that a political era has ended. Throughout the twentieth century Catholics, like Jews, were more likely than white Protestants to support an expanded role for government in the social and economic sphere to help the deprived in order to produce a "just society." We could say that this Catholic concern for community could be contrasted with the Protestant emphasis on individualism, and that this difference propelled them into the Democratic and Republican parties respectively. We can now observe that the commonality of cultural outlook on values has largely ended this party divide among churchgoing non-Hispanic whites. The implication for party politics is that a cohesive block of white Christian church members has emerged with a clear Republican Party orientation.

Ariela Keysar is a senior research fellow at the Department of Sociology at Brooklyn College of the City University of New York and was study director of the American Religious Identification Survey 2001. Barry A. Kosmin was principal investigator of ARIS 2001, which was carried out under the auspices of the City University of New York Graduate Center. This article is based on the authors' book, Religion in a Free Market, forthcoming from Paramount Market Publishing this summer.