This paper examines the effect of party affiliation on an individual's political views. To do this, we exploit the party realignment that occurred in the U.S. due to abortion becoming a more prominent and highly partisan issue over time. We show that abortion was not a highly partisan issue in 1982, but a person's abortion views in 1982 led many to switch parties over time as the two main parties diverged in their stances on this issue. We find that voting for a given political party in 1996, due to the individual's initial views on abortion in 1982, has a substantial effect on a person's political, social, and economic attitudes in 1997. These findings are stronger for highly partisan political issues, and are robust to controlling for a host of personal views and characteristics in 1982 and 1997. As individuals realigned their party affiliation in accordance with their initial abortion views, their other political views followed suit.