KYIV, Ukraine—The recent military tension between the U.S. and Iran underscores a new era of conflict, some military officials and analysts say, in which a country’s power on the world stage is no longer measured solely by economic clout, military force, or even diplomatic sway. Rather, the audacious use of misinformation to shape public opinion at home and abroad allows countries like Iran and Russia to punch well above their hard and soft power weight classes in shaping world events. To that end, experts say Iran has put into practice lessons in hybrid warfare that Moscow field-tested on the battlefields of Ukraine and later unleashed against Western democracies.“Iran’s attacks on oil tankers in the Gulf resemble, in their intent, Russia’s hybrid warfare operations that we have seen in Ukraine and elsewhere,” said Nataliya Bugayova, Russia research fellow at the Institute for the Study of War, a U.S. think tank.“Russia and Iran use hybrid warfare operations to advance their broader aims while trying to obfuscate reality on the ground and prevent the West from taking action to defend its interests,” Bugayova said, adding that Iran “has a history of learning from Russia on the battlefield.”In this new era of hybrid warfare, adversaries are able to threaten American security interests and undermine the U.S.-led democratic world without resorting to direct military action. Instead, by shifting the burden of conflict escalation onto the U.S., practitioners of hybrid warfare test whether American leaders are willing to retaliate against nonlethal, “gray zone” activities with lethal military force.