What is the main conflict in Gender Trouble: Feminism and the Subversion of Identity by Judith Butler?

Judith Butler's Gender Trouble begins with a seemingly simple question. In recent years, many feminists have defended the idea of a concrete feminine identity because they believe it is crucial for advancing the interests of women. Without a focal point conception of women, feminist identity politics would not be possible. However, as Butler points out, there are various postmodern and post-structuralist reasons to worry about the very idea of concrete identities much less the idea of well-defined, non-social conceptual boundaries. So, this leads to Butler's focal question: Can feminist identity politics survive without a feminist identity?