If opsec is good their keys are not confiscatable. If they gave them up then that’s on them.

There would be massive legal battles and huge blow back from Bitcoiner’s and cypher punk types.

Bitcoin would still work. New radicalized anon devs would likely step up globally. Spot price would take a hit but tick tock and global adoption would continue.

I know personally my resolve wouldn’t waver. I’d move out of the US and renounce citizenship for sure though. I bet > 100,000 other Bitcoiner’s would too.