Ashraf Ghani has completed his first visit to the United States as Afghanistan's President, cutting a very different figure from his predecessor, Hamid Karzai. But public diplomacy is one thing. Security in a corrupt home country is another. After President Obama agreed to extend the US presence in Afghanistan, President Ashraf Ghani addressed a joint meeting of Congress. He used words America never heard from his predecessor — despite all the dollars spent and the lives lost in his country.