Nuclear war is unthinkable. At least, that’s what we like to tell ourselves. Given the mass death and devastation from an atomic strike, surely only a desperate despot would even consider such a strike.

Well, think again. A new study finds that, among the American public, the taboo against the use of nukes is far weaker than you might imagine.

“When people are faced with scenarios they consider high-stakes, they end up supporting—or even preferring—actions that initially seem hard to imagine,” said Daryl Press, an associate professor at the Dartmouth College Department of Government....