"In effect, the law produces and then conceals the notion of a "subject before the law" in order to invoke that discursive formation as a naturalized foundational premise that subsequently legitimates that law's own regulatory hegemony."
This sentence refers to the problem Butler identifies with categorizing gender. By identifying 'woman', it creates the assumption that what is named by this word is different, that a binary exists, and therefore the axes of power constrain and impact everything having to do with womanhood, women and femaleness. This is further solidified throughout the text, as exemplified by other quotes chosen by classmates - Butler believes that our lives are systemized through law, that law is the process by which these distinctions are created, and then naturalizes them by legislating this order. Butler is, quite literally, challenging feminists to think outside of the box that is created by the political system that works to legislate and define our lives.