No, it's an assumption that the people discussing the subject are sane and rational. It's one thing to argue that the US devaluing its wildly overvalued dollar is an effective default. Nobody would disagree with that, that's why we did it - to give us the continual option for rugpulls. But it's simply delusional and unserious to insinuate that the US won't just print paper to pay off nominal debt. It costs the US absolutely nothing.
If the US doesn't do it and defaults, it props up the value of foreign-held treasuries by giving debtors a claim, it doesn't reduce it. We happily let the presses run since 2008, running up the stock market by nearly an order of magnitude, and didn't see a drop of inflation until the last presidential term.
Also, it's extremely weird that European elites think of NATO as some kind of local government. It's simply a US-invented and controlled institution that it used to pressure Russia (the US's competitor in a bipolar world), has had nothing but a corrosive effect in Europe, and now they do the job for free.