What if (and I realize this is an extremely pessimistic take) their plan is to just default on the debt and rely on military blackmail? Sure, there's a Constitutional prohibition on questioning the validity of USA debt, but the administration shrugs at the Constitution on a weekly basis. The endless whining about how 'unfairly' other nations are treating the US, 'ripping us off', 'laughing at us' etc is a precursor for aggressive action, and I think it's quite likely that at some point they'll come out and say 'we don't have to pay debts to countries that have been scamming us the whole time.' About one quarter of the population will support MAGA no matter what, and if things get bad enough the administration can just announce they've been 'forced' to take over Greenland and Canada.
A flashing negative warning sign of this would be issue of new kinds of Treasury securities with new complex rules.
That sounds like it would completely destroy the US economy and government budgets (at which point the only thing left to do is to establish a war economy under authoritarian rule and continue war? I don't even know, it sounds completely bananas...)
A flashing negative warning sign of this would be issue of new kinds of Treasury securities with new complex rules.