Some cyber operations are conducted independently to collect intelligence, penetrate networks, or create strategic effects without employing conventional military force. A cyber attack that causes the public to question its drinking water, for example, becomes psychological as much as operational. The decision ignited protests and diplomatic outrage from Moscow, and, within days, a wave of coordinated cyber attacks unlike anything the world had previously witnessed. The cyber attacks struck at Estonia’s confidence in the very institutions that had defined its remarkable post–Cold War transformation. The greater danger today may be that democratic societies remember the last cyber attack only until the next crisis arrives.