Studies of transgovernmental activities have enhanced our understanding of changing global politics, but their claims have not been fully investigated with respect to the security realm. Therefore, this article first acknowledges a gap between the practices and capacities of nonstate entities creating transnational threats and those of state-based agents of response. States' ability to respond to these threats has been questioned. Is this skepticism warranted or have states begun adapting and developing new responses to address nonstate security challenges? This article looks at transgovernmental responses to transnational terrorism and identifies an unconventional group of substate pioneers, police liaison officers (PLO), making moves into the transnational realm. Data collected through interviews with international PLOs reveal these activities to be characterized by increasing informality, depoliticization, and demonopolization of global security cooperation. This cooperation nevertheless maintains its strong ties with state legitimacy and capacity, and is therefore conceptualized here as statist transnationalism.