The overarching question imparting urgency to this exploration is: Can U.S.-Russian contention in cyberspace cause the two nuclear superpowers to stumble into war? In considering this question we were constantly reminded of recent comments by a prominent U.S. arms control expert: At least as dangerous as the risk of an actual cyberattack, he observed, is cyber operations’ “blurring of the line between peace and war.” Or, as Nye wrote, “in the cyber realm, the difference between a weapon and a non-weapon may come down to a single line of code, or simply the intent of a computer program’s user.”
Survey experiments have demonstrated that although the American public prefers using conventional to nuclear weapons, if all else is equal, this preference readily gives way to the desire to keep compatriot soldiers safe or to maximize the effectiveness of U.S. military operations to protect the homeland. We know little, however, about how the publics of other nuclear weapons states assess the use of nuclear weapons and non-combatant immunity. A survey experiment given to a representative sample of American, British, French, and Israeli citizens reveals that categorical reasoning, namely a nuclear taboo and an absolute prohibition on intentionally targeting civilians, does little to shape public opinion. A majority or near majority of respondents are willing to support nuclear use if it is deemed more effective and foreign civilian fatalities are low; yet almost a third of respondents are willing to kill 100,000 foreign civilians in order to prevent a terrorist attack estimated to kill 3,000 compatriot civilians in their homeland. The results also show that Israeli respondents display the most hawkish preferences across many scenarios, while the British public is consistently the least willing to support nuclear weapons or targeting civilians. French and American citizens are roughly equally hawkish. Scott D. Sagan, in this seminar based on a paper co-authored with Janina Dill and Benjamin A. Valentino, shows that compatriot partiality—the extent to which citizens prioritize sparing compatriot over foreign civilians—plays a key role in explaining these cross-national differences in the support for the use of nuclear weapons.