As a subsidiary company, does Amazon retain operational control over that branch?
If so, it's subject to the CLOUD act, and therefore, not compatible with EU rules.
> Amazon remains the owner and controls the technology, yes.
So, basically, the answer is that the EU subsidiary is not independent. Consider Lavabit's story, the US admin would have no issue asking Amazon to trojanize their tech.
> their reputation will be forever ruined
That happened 20 years ago.
> It's not in Amazon's corporate self-interest to allow a back door like that.
They wouldn't have a say in the matter.