derekullo :
"Is the United States legally able to ask nicely for information stored in other countries that pertains to a citizen of the United States"
Countries are free to say no.
jasonkaler :
That can request all they want, but if the country they're requesting from...
They're not asking a foreign country, they're asking a domestic company to provide (a copy of) information stored abroad.
The country in which the data is stored doesn't get involved in any way!
Getting a go-ahead here should off course trigger the response to ban non US local and national governments from having any connection to US IT companies such as Microsoft, Google, Facebook, Yahoo, Amazon, etc. (Just like US officials are now banned from using Kaspersky products.)
And also, off course, a recommendation for regular citizens not to use these products.