CAMBRIDGE: The world of traditional power politics was typically about whose military or economy would win. In today's information age, politics is also about whose "story wins. National narratives are, indeed, a type of currency. Governments compete with each other and with other organizations to enhance their own credibility and weaken that of their opponents. Witness the contest between the government and protesters after the Iranian elections in June 2009, in which the Internet and Twitter played crucial roles, or the recent controversy between Google and China. Reputation has always mattered in world politics, but credibility has become crucial because of a "paradox of plenty. When information is plentiful, the scarce resource is attention. Under the new conditions, a soft sell may, more than ever, prove more effective than a hard sell. For example, the relative independence of the BBC, sometimes a source of consternation to British governments, has paid rich dividends in credibility, as illustrated by this account of Tanzanian President Jakaya Kikwete's day: "he rises at dawn, listens to the BBC World Service, then scans the Tanzanian press. Skeptics who treat the term "public diplomacy as a mere euphemism for propaganda miss the point. Simple propaganda is counterproductive as public diplomacy. Nor is public diplomacy merely a public-relations campaign. Public diplomacy also involves building long-term relationships that create an enabling environment for government policies. The contribution of direct government information to long-term cultural relationships varies with three dimensions or stages of public diplomacy, and all three are important. The first and most immediate dimension is daily communications, which involves explaining the context of domestic and foreign-policy decisions. This dimension also involves preparation for dealing with crises. If there is a vacuum in information after an event, others will rush in to fill it. The second dimension is strategic communication, which develops a set of simple themes, much as a political or advertising campaign does. While the first dimension is measured in hours and days, the second occurs over weeks, months, and even years. The third dimension of public diplomacy is the development of lasting relationships with key individuals over many years or even decades, through scholarships, exchanges, training, seminars, conferences, and access to media channels. These programs develop what the American journalist Edward R. Murrow once called the crucial "last three feet - face-to-face communications, with the enhanced credibility that reciprocity creates. But even the best advertising cannot sell an unpopular product. A communications strategy cannot work if it cuts against the grain of policy. Actions speak louder than words. All too often, policymakers treat public diplomacy as a bandage that can be applied after damage is done by other instruments. For example, China tried to enhance its soft power by successfully staging the 2008 Olympics, but its domestic simultaneous crackdown in Tibet - and subsequent repression in Xinxiang and arrests of human rights lawyers - undercut its gains. Great powers try to use culture and narrative to create soft power that promotes their advantage, but they do not always understand how to do it. Critics in the United States complain that the over-militarization of foreign policy undercuts its credibility. Instead, they advocate diplomacy "on steroids, staffed by diplomats trained in new media, cross-cultural communications, granular local knowledge, and networks of contacts with under-represented groups. The centralized mass-media approach to public diplomacy still plays an important role. Governments need to correct daily misrepresentations of their policies, as well as to try to convey a longer-term strategic message. The main strength of the mass-media approach is its audience reach and ability to generate public awareness and set the agenda. But its weakness is its inability to influence how the message is perceived in different cultural settings. The sender knows what she says, but not always what the targets hear. Cultural barriers are apt to distort what is heard. Networked communications, on the other hand, can take advantage of two-way communications and peer-to-peer relations to overcome cultural differences. This type of decentralization and flexibility is difficult for governments to accomplish, given their central accountability structures. The greater flexibility of non-governmental organizations in using networks has given rise to what some call "the new public diplomacy, which is no longer confined to messaging, promotion campaigns, or even direct governmental contacts with foreign publics serving foreign-policy purposes. It is also about building relationships with civil-society actors in other countries and facilitating networks between non-governmental parties at home and abroad. In this approach to public diplomacy, government policy is aimed at promoting and participating in, rather than controlling, such cross-border networks. Indeed, too much government control, or even the appearance of it, can undercut the credibility that such networks are designed to engender. The evolution of public diplomacy from one-way communications to a two-way dialogue treats publics as co-creators of meaning and communication. Power in a global information age, more than ever, will include a soft dimension of attraction as well as the hard dimensions of coercion and payment. Combining these dimensions effectively is called "smart power. For example, the current struggle against transnational terrorism is a struggle over winning hearts and minds, and over-reliance on hard power alone is not the path to success. Public diplomacy is an important tool in the arsenal of smart power, but smart public diplomacy requires an understanding of credibility, self-criticism, and the role of civil society in generating soft power. If it degenerates into propaganda, public diplomacy not only fails to convince, but can undercut soft power. Instead, it must remain a two-way process, because soft power depends, first and foremost, upon understanding the minds of others. Joseph S. Nye, a former US Assistant Secretary of Defense, is a Professor at Harvard Univeristy and author of The Powers to Lead. This commentary is published by DAILY NEWS EGYPT in collaboration with Project Syndicate (www.project-syndicate.org).