The fact that the final three contenders in the US election race are a woman, an African-American, and an older man who often challenged his own party suggests that the United States, after a decline in popularity during the Bush years, retains some capacity to reinvent itself. But the next president will need to recognise that the nature of leadership also is changing.

The information revolution is transforming politics and organisations. Hierarchies are becoming flatter, and knowledge workers respond to different incentives and political appeals. Polls show that people today have become less deferential to authority in organisations and in politics. Soft power, the ability to get what you want by attraction rather than coercion or payment, is becoming more important.

Of course, hard power remains important too. Hard and soft power are related, because they are both approaches to achieving one's objectives by affecting the behaviour of others. Sometimes people are attracted to others who command hard power by myths of invincibility. As Osama bin Laden put it in one of his videos, "When people see a strong horse and a weak horse, by nature they will like the strong horse."

Hard and soft power can reinforce or undermine each other. Certainly, the US's use of hard power with military and police force was necessary to counter al-Qaeda, but the indiscriminate use of hard power (the invasion of Iraq, the Abu Ghraib prison photos, detentions without trial) served to increase the number of terrorist recruits. The absence of an effective soft power component undercut the strategic response to terrorism.

Those who rely on coercion are not leaders, but mere wielders of power. Thus, Hitler was not a leader. Even tyrants and despots need a degree of soft power, at least within their inner circle, to attract or induce henchmen to impose their coercive techniques on others. At the same time, except for some religious leaders, such as the Dalai Lama, soft power is rarely sufficient.

Indeed, psychologists have found that too much assertiveness by a leader worsens relationships, just as too little limits achievement. Machiavelli famously said that it is more important for a prince to be feared than to be loved. He may have been correct, but we sometimes forget that the opposite of love is not fear, but hatred. And Machiavelli made it clear that hatred is something a prince should carefully avoid. When the exercise of hard power undercuts soft power, leadership becomes more difficult, as President Bush found out.

Soft power is not good per se, and it is not always better than hard power. But it does allow followers more choice and leeway than hard power, because their views and choices matter more. Thus, in an age of flatter hierarchies and empowered knowledge workers, soft power is likely to increase in importance.
Hard power has not become irrelevant, but leaders must develop the contextual intelligence that allows them to combine hard and soft power resources into a 'smart power' strategy. Whoever the next president will be, he or she will need to learn that lesson.

(Project Syndicate)

Joseph S. Nye Jr is a professor at Harvard and author of The Powers to Lead.