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
What was the previous attempt? I’m falling behind in this gish gallop.
Tariffs
Last weekend it was the Mexico/Canada “25% tariffs” that he pussied out on and reversed his decision on both countries by Monday morning.
Just as a note Tariffs are back on (but only for steel/aluminum).