Since the rise of the New Christian Right in the 1970s and 1980s, evangelicals have become closely linked with the Republican Party and cultural issues like abortion and gay marriage. However, since 2006 a variety of political observers have debated whether or not evangelicals are becoming more liberal. In this dissertation, I study public opinion and political behavior among young evangelicals in order to provide a social scientific answer to this debate. Drawing on research from sociology, I argue that evangelicalism is a subculture that is engaged in society but holds certain values that are contrary to society. As part of its subcultural role, the evangelical tradition is at times highly critical of secular cultural norms and it uses various subcultural institutions to communicate alternative, evangelical values in their place. This means that evangelicalism may have the potential to insulate young evangelicals from broader trends in public opinion. This potential is strongest (a) among evangelicals who are more engaged in the subculture and (b) with regard to political identities and issues that have been more central to evangelicalism's political identity. In order to test various aspects of my theory, I rely on a multi-method approach that includes analysis of existing survey data, an original series of 42 interviews with evangelicals at five colleges, and an original panel study of evangelicals at seven colleges. I find that accounts of a new generation of liberal young evangelicals have been overstated: in terms of their partisan identity, ideology, and attitudes on abortion, young evangelicals are as conservative as ever. While young evangelicals have become more liberal on issues like gay marriage and social welfare, the liberalization seems to be concentrated among those who aren't engaged in the subculture. Using panel data and evidence from the interviews, I show that immersion in the evangelical subculture leads to increased ideological conservatism and more conservative attitudes on abortion and gay marriage. I conclude that my subcultural theory provides an effective framework for understanding patterns of public opinion among evangelical Millennials.