‘Nous sommes en guerre.’ Nicolas Sarkozy’s statement on Sunday morning, after meeting François Hollande to discuss the massacres in Paris, echoed his successor’s statement to the French people on Friday evening, which used the g-word four times. Modern statecraft deploys a mobile army of mixed metaphors, as when the ‘they’ who kill ‘us’ are also partly ‘us’. If it’s war abroad, does that mean that Friday’s killers count as combatants, with Geneva Convention rights, and that military action needs legal authorisation? If it’s domestic terrorism, what title does the state have to range beyond its borders, pursuing Isis on foreign sovereign territory?