Earlier this summer, after Iran downed an unmanned U.S. military aircraft, President Trump said he had approved — then put a stop to — a U.S. missile strike on Iran. Polling showed most Americans supported aborting the mission. One Harvard CAPS/Harris Poll survey found that 57 percent of voters opposed “military confrontation with Iran” unless Iran had attacked the United States. Only five percent of respondents wanted the United States to “declare war on Iran.” This unpopularity of intervening in Iran fits with larger public opinion trends. In a forthcoming article in the Journal of Conflict Resolution, I analyzed the results of more than 1,000 nationally representative survey questions about the use of force overseas. Collected from 1981 to 2016, these data reveal steady patterns in public attitudes that continue today, showing that Americans would hesitate to pick fights with governments not known for harming the United States or its allies. Here’s what I found.