In the years immediately before and after the 1998 Lysøen Declaration, a striking feature of the initiatives associated with the human security agenda was the prominent role of civil society coalitions, which was widely regarded as indispensible to the signal successes of this period. However, the dramatic breakthroughs of this “new diplomacy” were the products of a propitious conjuncture of conditions that contained the seeds of their subsequent loss of momentum. Yet the human security work of civil society organizations (CSOs) continues, in less prominent but still important ways, to be woven into the fabric of the more cosmopolitan practices promoted by the agenda. In the meantime, their setbacks contain important lessons-both for CSOs and for the policymakers inclined to collaborate with them.