Though the powder keg image is powerful, in reality very few wars start this way. It’s rare to see a minor incident like a border clash escalating or a preemptive war break out because one side attacks out of fear that the other side is about to attack.

About 20 years ago, I wrote that since 1816, preemptive wars have almost never happened. Further, many dangerous international crises — like the Berlin Crisis in 1958-1961 or the October 1962 Cuban missile crisis — did not escalate into preemptive wars.

More recently, the 1994 scare over a second Iraqi invasion of Kuwait did not prompt U.S. preemption. Chinese missile tests off the coast of Taiwan in 1996 did not spark war. And Russia’s recent provocative aerial and naval actions against other nations have not frightened the targets of such actions into preemption.