In November of 2008, as progressives celebrated the historic election of President Barack Obama, LGBT people and their allies watched in shock and disappointment as California voters passed Proposition 8, a Constitutional Amendment that revoked the rights of same-sex couples to marry. In the following days, people demonstrated their anger, shock, disappointment, and sadness at the Initiative's passage by joining marches, candlelight vigils and rallies. Many activists engaged in a period of sustained mobilization, gathering to debate the reasons for the loss and future goals and strategy. As a result, activists developed new movement infrastructures, constructed new collective action frames about same-sex marriage, and innovated new strategies and tactics for disseminating those messages. In this dissertation, I examine this period of mass mobilization as a case of reactive mobilization, or mobilization precipitated by the loss of power and status (Tilly 1978).

The study draws on qualitative data, including semi-structured, in-depth interviews with 47 key informants, participant observations, and an archive of documents about the movement to construct a history of the California marriage equality movement. I argue that the passage of Proposition 8 posed a serious threat to the legal and socio-cultural status of LGBT Californians and was a moral shock that compelled people to mobilize. The data suggests that a key feature of the post-8 reactive mobilization was that activists' emotional responses sustained their activism beyond the immediate protests and influenced how they organized. As they expressed their shock, anger, and indignation at the California "yes" voters, activists also expressed their anger with a No on 8 campaign from which they felt excluded.

Activists framed the loss as the result of the campaign's structural composition and hierarchical leadership structure that excluded the perspectives of grassroots activists and, in particular, activists within rural communities and communities of color. As a result, many activists emphasized building organizations that utilized new tactics, and that organized in communities of color, rural communities, and communities with little existing marriage equality infrastructure. Moreover, activists were critical of the No on 8 campaign's messaging which excluded images of and messages about same-sex couples and their families. Therefore, activists responded by emphasizing a right to love frame that drew on the shared cultural understandings of marriage as a universal legal and cultural rite and innovated tactics that required the conscious deployment of identity to communicate that frame to the public.

These tactics included using digital technology to project images and stories about their families' everyday lives, adapting existing tactics to teach one another to construct persuasive personal stories, and by utilizing traditional campaign tactics, such as canvassing neighborhoods, to educate voters through conversations that emphasized the voters' experiences and perceptions of marriage and same-sex couples and families. This dissertation expands the literature on the marriage equality movement and contributes to the social movement literature more generally by examining the roles of threat and emotions for mobilization.