This past weekend, Ambassador Samantha Power gave her first speech as U.S. Ambassador to the United Nations to more than 1,500 young activists at Invisible Children's Fourth Estate Leadership Summit in Los Angeles.

Fidel Castro turned 87 behind closed doors Tuesday, with official tributes in state media serving as a reminder that the clock is ticking on his revolutionary generation's grip on power. Castro stepped down as president following a near-fatal illness in 2006, and his successor, younger brother Raul, has said that his current term ending in 2018 will be his last, ostensibly ending nearly six decades of rule by the brothers.

Tina Turner did it. So did Facebook’s Eduardo Saverin. And Terry Gilliam of Monty Python fame. They all renounced their US citizenship. It doesn’t happen all that often–maybe a thousand a year. But it looks like the pace is increasing. According to the Wall Street Journal, more Americans gave up their US citizenship in the the first half of this year than in all of 2012 .Host Marco Werman talks with Marylouise Serrato, of American Citizens Abroad, about the trend.

Japan’s public diplomacy hovers between the ludicrous and the sinister. In recent months, the country has specialised in foreign policy gaffes that seem designed to give maximum offence to its Asian neighbours while causing maximum embarrassment to its western allies. Last week provided another example.

I often say in international relations there six things a country can do: ‘giving, helping, sharing, boasting, shouting, and fighting.’ This fits with Joseph Nye’s classic definition of ‘soft power’ coined in 1990 as ‘the ability to attract and co-opt rather than coerce, use force or give money as a means of persuasion.’ In an ideal world sharing culture and trade is a lot better than firing bullets or giving aid.

Diplomacy is an essential part of foreign policy. The postwar period saw the rise of public diplomacy, which went beyond traditional diplomacy in that it tried to influence public opinion in other countries. It dealt with influencing public attitudes on the formation and execution of foreign policy as private individuals began to engage in intercultural communication. Organized cultural visits like performances by philharmonic orchestras became part of public diplomacy.

On a sunny, crisp November day in 2008, three American civilians joined a platoon of United States soldiers on a foot patrol in Maiwand District, a flat, yellow patch of earth crowned by black-rock mountains in southern Afghanistan. The civilians were part of the Human Terrain System, an ambitious, troubled Army program that sends social scientists into conflict zones to help soldiers understand local culture, politics and economics.