China has definitely not stopped buying US Treasuries. As an example, in the 4Q ‘22 they bought $40B. The same applies to other countries with positive trade balances , such as Germany, Japan, Netherlands, Taiwan, OPEC members. They have no choice but for their Central Banks to buy $US Treasuries. They all have chosen to repress domestic demand and not allow their currencies to appreciate, and the only way to do that is buying foreign currency with their trade surplus.The public debt may be constitutionally valid, but the whole world knows we suppress interest rates and print money to pay the bill. Foreigners simply stopped buying our debts and invested their money elsewhere. China famously has sold most of their holdings and shifted to buying mines, ports, roads, and generally worldwide infrastructure projects instead. Since 2014, nada. Debt/GDP ratio this bad has only been fixed by inflating the money supply and impoverishing bond holders.
Also important to keep in mind that China buys and holds Treasuries through state owned banks and their parties in Europe, mostly Belgium, and also buys US mbs and agency debt, which has a different classification.
The weighed average maturity of US Treasury debt is a bit over 6 years, has been in that range for a number of years. This is hardly short term.We were unable to convince anyone to buy our longer dated notes, so we have refinanced from long to short duration for 30 years.
A huge benefit to refi a TBill from the 80's at 17% or some such ridiculous rate down to 2%. Within a few more years the long duration notes and higher interest rate notes will be gone. Meaning a sudden spike in interest rates has an immediate effect on FICA and Medicaid and Military budgets.
Hindsight is usually 20/20, and the US Treasury may come to rue not adding more long term debt during the years when it was very cheap. Nonetheless, there are a fixed number of buyers of very long debt, mostly insurers, pension funds and Central Banks, and their needs are satisfied with the current volume. The growth in demand for Treasuries has been in money market, hedge funds and shadow banks, and they want shorter term paper that is more liquid and can be traded more easily.
Not sure what California has to do with a US debt level discussion and these numbers look exaggerated, but there are no reputable or serious projections of US federal spending and borrowing that approximate them.California went from something like $100B surplus to $30B deficit in 9 months. Fedgov finances will have similar volatility.