The American economic boom couldn't have happened without China's willingness to buy up American debt. While the American economy has hit a road bump (or maybe a pothole), China has been able to avoid the same market turmoil. Until now. With a downturn in its own economy, China isn't interested in acquiring any more American debt and that is having a profound impact on our ability to borrow. New York Times' reporter Keith Bradsher is following this story in Hong Kong.