Krugman has this to say about it:
For those not familiar with how financial markets work, US Treasuries are the ultimate safe asset, used as collateral for everything. Even a hint that some Treasuries might not be honored could bring everything to a screeching halt
Musk and Trump are both in the habit of stiffing people they owe money. If markets even suspect that this habit will extend to Treasuries, God help us
Sort of funny that as soon as the greatest generation died their children, who were too stupid to understand what they had built, destroyed their empire
Boomers have never once in their miserable little lives understood that their favorite Facebook meme calls them the weak men.