Joseph Nye has an excellent blog post: Barack Obama and Soft Power on today's The Huffington Post, articulating why Obama's style of Soft Power is so necessary for America's international influence. When I lived in London my co-workers were cautiously optimistic that Obama would become President. There concerns are well articulated in Nye's post.
Nye is the author of The Powers to Lead (2008) which I haven't read yet but is now on my short list of books to devour.