Who owns the US fed'l govt's debt? Well, the US gov't for one thing. Huh?
Look at the blue section. That the part of the 17 billion dollar debt that the US bought up. If we don't pay up soon, Uncle Sam may have to come around to your front door and break his own kneecaps.
Also, note how much of the debt is owned by Japan. Why all the panic about Chinese banks owning US debt? Japan's just as big a holder. And speaking of holders, what with that big chunk of "Caribbean banks" holding our papers? Now think about who invests in Caribbean banks for a second. Yup, that's code speak for the 1%ers investing their dollars in US debt collection.
So the debt is one problem. People who are fiscally invested in the US continuing to run up its debt is a different problem.
(on edit: source is NPR, but I've seen similar information from other sites over the past 8 years as an economics teacher. The Caribbean banks section has been the fastest growing sector of the "foreign" debt in recent years)