Sexual Freedom and the History of the Left

The political and cultural Left, which stand for increasing the scope of freedom, have shifted positions historically on issues of sexuality. For instance, where once the Left challenged marriage and family norms in society, there has been a turn to advocating participation in predominant institutions, for instance gay marriage: there has been some conflict in LGBTQ circles over the politics of gay marriage, whether it should be advocated in certain ways or at all by the Left. What do such controversies tell us about the politics of sexual freedom and the history of the Left, moving forward? How are issues of sexual freedom related to issues in the greater society and not of concern merely to sexual minorities and subcultures? Is there simply a narrative of historical progress, as expressed for example in President's Obama's recent Second Inaugural Address? Or might we look forward to renewed political disputes around issues of sexual freedom? What can history teach us about this?