Every Patriot interceptor fired from US defence positions stationed close to the frontline of the Iran war costs $4 million (€3.7m). The Iranian Shahed drone it destroys costs, at most, tens of thousands of euros. ADVERTISEMENT ADVERTISEMENT Somewhere in that gap lie some of the most crucial lessons Europe needs to absorb as it plans its future defence spending. According to Bruegel, the defence calculus has fundamentally changed. Precision drones and missiles, once carrying a hefty price tag