Counter-Terror by Proxy sheds lights on a fascinating and intriguing case of illiberal practices in a liberal regime where Spanish State agencies colluded with mercenaries and petty criminals in order to kill members of the Basque militant group ETA and push the French Government towards more cooperation in the fight against Basque terrorism.It assesses the political and institutional context of the inception of this blatant detour from legality, interrogating the logics and rationale at stake and offers a thorough examination of the implications of the use of unorthodox counter-terrorist strategies in a liberal democracy.