This book talks about the unique role of the United States over the past century, and what it would mean if the role of the U.S. in the international system would decrease in the future.
The author makes a good case that the influence of the U.S. has been largely positive, certainly compared to the alternatives. He also decries the commentators who say that America's influence is on the wane -- in his view, America's influence since WW2 has always been a decidedly mixed story, with many failures and humiliations in the international arena -- and that this is nothing new.
"when American power declines, the institutions and norms American power supports will decline too."
The author is not starry-eyed or naive about the real-politik the U.S. has often played, but convincingly makes the argument that it is better for the world if the U.S. is powerful and engaged.
This was an interesting book to read. It's good that it's short -- the argument becomes a little repetitive -- but it was a convincing read.