Soft power grows out of a country’s culture, its political values and its foreign policies. In the short term, hard power usually trumps soft power. But over the long term, soft power often prevails.

Joseph Stalin once mockingly asked, “How many divisions does the pope have?” But the papacy continues today, while Stalin’s Soviet Union is long gone.

When you are attractive, you can economize on carrots and sticks. If allies see you as benign and trustworthy, they are more likely to be open to persuasion and follow your lead. If they see you as an unreliable bully, they are more likely to drag their feet and reduce their interdependence when they can.

Cold War Europe is a good example. A Norwegian historian described Europe as divided into a Soviet and an American empire. But there was a crucial difference: The American side was “an empire by invitation”. That became clear when the Soviets had to deploy troops to Budapest in 1956 and to Prague in 1968. In contrast, NATO has not only survived, but also voluntarily increased its membership.

A proper understanding of power must include both its hard and soft aspects. Machiavelli said it was better for a prince to be feared than to be loved, but it is best to be both. Because soft power is rarely sufficient by itself, and because its effects take longer to realize, political leaders are often tempted to resort to the hard power of coercion or payment.

When wielded alone, however, hard power can involve higher costs than when it is combined with the soft power of attraction. The Berlin Wall did not succumb to an artillery barrage; it was felled by hammers and bulldozers wielded by people who had lost faith in communism and were drawn to Western values.