Ivo Daalder, a former U.S. ambassador to NATO, is a senior fellow at Harvard University’s Belfer Center and host of the weekly podcast “World Review with Ivo Daalder.” He writes POLITICO’s From Across the Pond column . The U.S. has the most powerful military in human history. It also hasn’t won a war in more than 30 years. Since 1945, the U.S. has fought major wars in Korea, Vietnam, Afghanistan, Iraq and now Iran. Among them, only the 1991 Gulf War counts as a genuine success — and even that