Nobody Knows Where the Red Line Is for Cyberwarfare

A common explanation for why the Soviet Union never used nuclear weapons during the Cold War was the expectation that any attack would likely prompt a devastating nuclear response. The fear of mutually assured destruction was enough to keep both the USSR and the U.S. from launching a nuclear attack, even as they spent decades building up huge stockpiles of weapons.

Cyberweapons are different. Cyberattacks by both governments and private hackers have exploded in recent years. Many of these are financially motivated, but others involve espionage or, in several high-profile cases, the sabotage of physical infrastructure. There’s broad agreement ...