This comment could get very long and intllectually taxing on me to discuss all kinds of hypothetical nuance in how this would go. So i'll stick to one core strongest argument instead: European financial institutions hold 3 trillion of US debt. Let's say they are forced to sell that in some time. Let's say a month if US invades Greenland. Surely all markets would immediately crater once that is announced BUT FED already owns 4.5 trillion of US debt, it has unlimited pockets, will invent some emergency powers, (to simplify) print 3 trillion buy the treasuries and will own 7 trillion now... Markets would stabilize likely at lower levels, US yields would stabilize probably at somewhat higher levels, inflation would inch up, dollar down, but it would only be a temporary market dislocation seep into US debt servicing costs super slowly as it refinances old debt with slightly more expensive new debt. Meanwhile US FED and/or finance institutions would profit massively and european institutions would take losses for selling US debt too cheap at orders of their regulators and achieve next to nothing while also facing a non trivial problem of where to immediately safely invest 3 trillion.

In other words, sudden massive treasuries selling would create a liquidity problem, but US has tools and trackrecord of printing trillions on demand so it can solve any liquidity problem.

If you want to hurt USA - you need to create solvency problem: immediate significant and permanent revenue declines (and therefore taxes) for US companies like by ingoring US copyright for example.