A large and growing proportion of Americans claims to be neither Republican nor Democratic, and partisan independence is most wide-spread among young adults. A time-series cohort analysis of eleven surveys conducted by the Survey Research Center of the University of Michigan between 1952 and 1974 strongly suggests that the low level of partisan identification among young adults results largely from fundamental differences between their socialization and that of their elders. The overall decline in party identification results largely from generational change. High levels of partisan identification persist among persons who entered the electorate before World War II, but among those who entered the electorate more recently levels of identification are low. The analysis strongly suggests that overall levels of party identification will continue to decline, and permits examination of one process by which party loyalties among mass electorates gradually are transformed.