If you really want to get into the complexities of who holds US debt and what happens if some of it is cancelled or whether than can happen, that's a huge discussion taking weeks of work and requireing PhDs to answer.

I'm just making quips about how much debt has been run up since 2008 and how little the US (or other nations that have followed the same policies) actually has to show for it compared to what it will take to pay it off...