Re: Once again - US cloud service. Two words from Europe.
The PATRIOT Act empowers the security services to force Amazon* to provide the information they request (secretly - you'd never know about it). Wherever that information is held, and irrespective of any contract Amazon agreed to.
If Amazon don't comply - irrespective of why - it's serious jail time for the execs.
Did you even bother to read the comment you replied to? Amazon are in the clear if they fail to provide information they don't have access to, just as you are if they demand you hand over e.g. Russian nuclear launch codes. The current Microsoft case hinges on the extent to which access can be inherited from a wholly-owned subsidiary. If you can't see the difference I'd suggest steering clear of commenting on legal matters.