By analyzing a white Christian subsample of pooled national survey data collected in 1968, 1970, and 1972 (subsample'sn =4,142), we try to determine whether ethnicity has a direct effect on party identification net of parental party identification. In so doing, we raise a number of subsidiary issues: (1) how best to measure ethnicity, (2) the need to distinguish between ethnically identified and ethnically assimilated respondents, and (3) possible regional variation in the impact of ethnicity. We find that religion alone (Protestant versus Catholic) is an adequate measure of ethnicity for this analysis, there being little intrareligious variation in party identification by national origin. Second, religion's effect is largely limited to the ethnically identified. Third, its effect holds up when controlling for parental party identification and SES. Fourth, regional variation in the impact of religion is understood as largely flowing from regional variations in the distribution of Catholics.