Edward Snowden exposed the discrepancy between the official US defence discourse of liberal values in cyberspace and secret surveillance and cyber exploitation practices. Situated in the critical literature on security and surveillance, the article proposes that more attention needs to be paid to the constitutive role of transgressive practices for security communities. The article introduces a Lacanian strategy for studying transgression in the US cyber defence community. Through this strategy, a transgressive other – in this case, China in cyberspace – enters the fantasy of the US cyber defence community as the symptom that conceals more fundamental tensions in the US cyber defence. But the community's representation of China in cyberspace represents more than that; China is a fantasmatic object that structures and gives content to a desire for transgressing the official ideals of the US cyber defence. This is why the excessive cyber practices that China is criticised for conducting mirror the secret, disavowed transgressions of the US cyber defence. Transgressions, the article concludes through Lacan, provide the necessary (partial) enjoyment that sustains the US cyber defence community as a solidarity-in-guilt and the official US cyber defence discourse.