CAMBRIDGE – Two years ago, Barack Obama was a first-term senator from a mid-western state who had declared his interest in running for the presidency.

Many people were skeptical that an African-American with a strange name and little national experience could win. But as his campaign unfolded, he demonstrated that he possessed the powers to lead – both soft and hard.

Soft power is the ability to attract others, and the three key soft-power skills are emotional intelligence, vision, and communications.

In addition, a successful leader needs the hard-power skills of organizational and Machiavellian political capacity. Equally important is the contextual intelligence that allows a leader to vary the mix of these skills in different situations to produce the successful combinations that I call "smart power.”

During his campaign, Obama demonstrated these skills in his calm response to crises, his forward-looking vision, and his superb organizational ability.

In addition, his contextual intelligence about world politics has been shaped from the bottom up with experience in Indonesia and Kenya, and his understanding of American politics was shaped from the bottom up as a community organizer in Chicago.

Obama continued to demonstrate these leadership skills in his almost flawless transition.

By selecting his primary opponent, Hillary Clinton, as his Secretary of State, and reaching across party lines to retain Robert Gates as Secretary of Defense, he showed openness to strong subordinates.

In his inaugural address, he sounded the themes of smart power – a willingness "to extend an open hand to those who unclench their fists” – but also stressed themes of responsibility as Americans confront sobering economic problems.

Moreover, Obama has started his term in decisive fashion. In his first weeks in office, he began to fulfill his campaign promises by outlining a massive economic stimulus plan, ordering the closure of the Guantánamo Bay prison, promoting new fuel-efficiency standards to save energy, giving an interview to Al Arabiya, and sending a top emissary to the Middle East.

George W. Bush once said that his role as leader was to be "the decider.” But even if Bush had been better as a decider, people want something more in a leader. We want someone who reinforces our identity and tells us who we are. We judge leaders not only by the effectiveness of their actions, but also by the meanings that they create and teach. 

Most leaders feed upon the existing identity and solidarity of their groups. But some leaders see moral obligations beyond their immediate group and educate their followers.

Nelson Mandela could easily have chosen to define his group as black South Africans and sought revenge for the injustices of Apartheid and his own imprisonment.

Instead, he worked tirelessly to expand the identity of his followers both by words and deeds. When Obama was faced with a campaign crisis over incendiary racial remarks by his former pastor, he did not simply distance himself from the problem, but made use of the episode to deliver a speech that served to broaden the understanding and identities of both white and black Americans.

The crisis on September 11, 2001, produced an opportunity for Bush to express a bold new vision of foreign policy. But he failed to produce a sustainable picture of America’s leadership role in the world. A successful vision is one that combines inspiration with feasibility.

Bush failed to get that combination right. 

Obama will need to use both his emotional and contextual intelligence if he is to restore American leadership. Contextual intelligence is the intuitive diagnostic skill that helps a leader align tactics with objectives to produce smart strategies in different situations.

A decade ago, the conventional wisdom was that the world was a uni-polar American hegemony. Neo-conservative pundits drew the conclusion that the United States was so powerful that it could do whatever it wanted, and that others had no choice but to follow. 

This new unilateralism was based on a profound misunderstanding of the nature of power – that is, the ability to affect others to get the outcomes one wants – in world politics.

The US may be the only superpower, but preponderance is not empire. America can influence but not control other parts of the world. Whether certain resources will produce power depends upon the context.

To understand power and its contexts in the world today, I have sometimes suggested the metaphor of a three-dimensional chess game. On the top board of military power among countries, the US is the only superpower.

On the middle board of economic relations among countries, the world is already multipolar. America cannot get the outcomes it wants in trade, antitrust, or other areas without the cooperation of the European Union, China, Japan, and others.

On the bottom board of transnational relations outside the control of governments – pandemics, climate change, the drug trade, or transnational terrorism, for example – power is chaotically distributed. Nobody is in control. 

This is the complex world in which Obama takes up the mantle of leadership. He inherits a global economic crisis, two wars in which US and allied troops are deployed, crises in the Middle East and South Asia, and a struggle against terrorism.

He will have to deal with this legacy and chart a new course at the same time. He will have to make difficult decisions while creating a larger sense of meaning in which America once again exports hope rather than fear. That will be the test of his leadership.

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