> What are the theatres where the US is supposed to be able to put on a strong showing? It doesn't seem to be Europe, they've got war on their doorstep and if anyone thinks the US is helping they should reflect on their reasoning
I think you have this backwards: the US was helping considerably, and then got taken over by pro-Russian conspiracy theorists.
But the bond stuff isn't "tribute" or nationalism; remember, it's being made by private sector investors, not national governments. Fairly straightforward calculation: which way is the exchange rate expected to move? Interest rate? Risk of default?
Up till now the US offered moderate interest rates, favourable direction of exchange rate movement, and imperceptible risk of default. There's still no reason to default other than madness and a desire to strap on the suicide vest and become Argentina.