Fitch's decision yesterday to lower the US' credit rating for a pristine AAA to AA+ is still reverberating through global financial markets and has helped spark a heated - some say healthy - debate over the level of the country's federal borrowing. America's debt ratio as a proportion of its economy is over two and a half times the average of nations that currently have a AAA rating. Senator Joe Machin (D-WV) today called the debt crisis a fiscal runaway train. Joining Julia to discuss is Fitch co-head of Americas sovereign ratings Richard Francis. To learn more about how CNN protects listener privacy, visit cnn.com/privacy