Invoking the universal jurisdiction doctrine, the Center for Constitutional Rights tried first in Switzerland and then in Canada to prosecute former President George Bush, on behalf of four tortured detainees. Bush cancelled his trip to Switzerland after news of the potential warrant came to light. Bush has traveled to Canada, but the Canadian government shut down the prosecution in advance of his arrest. The Center has filed a grievance with the United Nations for Canada's failure to enforce the Convention Against Torture, on which action is pending.