I’m no economist and will probably get this wrong, but since there is nobody else here… least I can do is give you enough an answer that someone more knowledgeable will come and correct me.

Basically, governments can print magic slips of paper called “bonds” that people will want to buy for two primary reasons: (1) they get interest when they hold the bonds (interest paid by taxes), and (2) the bond is considered a safe way to store value (like how a house is considered a safe way to store value). The government, in return for selling those magic pieces of paper, gets the money used to buy the bonds. It’s the Treasury Bond market.

Now here’s two important details about the bond market: (1) Bonds have an inverse relationship with cost and interest rates. If stockpiles of bonds get sold, that increases the supply of bonds which causes price to fall — adversely causing interest rates to hike up. (2) Because U.S. Treasury bonds are considered risk-free, all other interest rates in the economy (mortgages, car loans, corporate debt) are built on top of the Treasury yield (Example: If a 10-year Treasury yields 5%, a bank might offer a 10-year mortgage at 5-6%). Basically, Treasury rates set the floor for almost all borrowing costs.

So if a foreign state sells massive quantities of bonds, interest rates everywhere can shoot up. That can make all of our existing debt too difficult to pay back. We’d be stuck with three options if it gets bad enough: (1) default on the debt, (2) debase our currency by printing enough money to push the problem down the road, or (3) balance the governments budget.

From what I understand, we’ve already pushed the limits of option 2 during the Housing Crisis and COVID. Printing more money is talked about as though it’s impossible without causing more harm than good. Honestly, I don’t know what happens if the bond market cracks at this point… a depression comparable to TGD?