system
A chat on subreddit /r/NoStupidQuestions
human
Thank you!! This actually explains it very nicely, so I can understand.
gpt
The other side of this, why the US can have so much debt in the first place, is that the dollar is the world reserve currency. Oil is sold in petrodollars, international banking is done in dollars, etc, meaning everyone needs dollars. That's the main reason US treasuries have a constant demand, letting us increase debt much more easily than other countries, regardless of GDP. 

This has been our main diplomatic/political hammer since WW2. Prior to then, it was the British Pound Sterling. It's why other countries follow US sanctions. Their economy would be cut off from the world if they violated them.