Over the decade and a half since the 9/11 attacks, calls for more international counterterrorism cooperation have become a stock element of political leaders’ speeches. Following each successive terrorist attack, leaders have underscored the need for greater collaboration among military, intelligence, law enforcement and criminal justice officials to counter increasingly transnational threats. These calls have been echoed at the multilateral level, with the UN and regional organisations adopting resolutions reiterating the need for intensified interstate co-operation and outlining steps that national governments should take to address the threats facing them….