It's backed by bonds, they have to pay. The US pays interest as well, on top.
If the US doesn't pay then they get downgraded. If they get downgraded (Moody's etc..) then no countries will buy bonds. The US gets junk bond status (ie - Greece), the feds have no money to give to the banks, banks cannot lend, the currency grows weak, the greenback becomes worthless and the economy essentially collapses.
So I am not sure what you mean by China not getting their portion.
Both Russia and China threatened to dump their preferred stocks and bonds in the middle of the 2008 financial crisis and the US shit their pants.
Learn to Macro Economics.
If the US doesn't pay then they get downgraded. If they get downgraded (Moody's etc..) then no countries will buy bonds. The US gets junk bond status (ie - Greece), the feds have no money to give to the banks, banks cannot lend, the currency grows weak, the greenback becomes worthless and the economy essentially collapses.
So I am not sure what you mean by China not getting their portion.
Both Russia and China threatened to dump their preferred stocks and bonds in the middle of the 2008 financial crisis and the US shit their pants.
Learn to Macro Economics.