Over the last generation, partisan polarization on “culture war” issues has become a defining feature of American politics, with the Democratic Party embracing social liberalism and the Republican Party embracing social conservatism. This was not always the case; for much of the 20th century, social issues such as abortion rights and LGBT rights played virtually no role in politics. Today, of course, they are central to partisan conflict. This transformation, despite its importance, is not well understood. In fact, there is little consensus among political scientists as to its timing, sequence, or causes. Using a variety of data sources, particularly a newly compiled set of historic state-party platforms, we aim to answer several crucial questions: Where and when did the partisan divide begin on abortion and gay and lesbian rights? Which party "moved first"? Was there a critical moment, or was position change incremental? Do abortion and gay rights follow the same pattern? While it is possible that the rise of social issues took place entirely on the national stage, then later spread to state and local politics, we set out to explore the possibility that these debates took place first at the state level. The data we will be collecting this summer include state legislative roll call votes on relevant bills, local media coverage of abortion and LGBT rights, and debates within the political parties about position-taking on these issues. We will focus on four case study states---California, Texas, Minnesota, and Massachusetts---during the 1970s and late 1960s.