By JEFFREY D. SACHS Source :NY Times PRESIDENT OBAMA has embarked on a promising new course to fight hunger and promote economic growth and political stability in countries like Cambodia, Honduras and Malawi. These countries, and many more, have large populations of impoverished farm families. Tough climates, environmental degradation and a lack of modern farm technology often limit food production to one-third or less of its potential. President Obama recently called upon Congress to double financial support for agricultural growth in developing countries to more than $1 billion in 2010. His program aims to help smallholder farmers get things like better seeds, fertilizer, small-scale irrigation and access to markets so they can overcome hunger and break out of extreme poverty. This new program could have amazing results — if it is properly carried out. A crucial factor in determining the program’s success will be how Washington delivers aid to the farmers. The traditional approach, a...