[dictum]

A country cannot be on the United States' good side without bending to its will. Also, the governments of other countries would love to have a peek on whatever intel the NSA has regarding their enemies.

So, if the US wants your data, they have great diplomatic resources to compel a country to hand it (read: CIA). I'm speculating as I don't know if there is a precedent of the US requesting data from another country using secret warrants, but as long as they have a warrant and the country does not have an overtly adversarial relationship with the US, it's a target.

Based on their tradition of bank secrecy, Switzerland may be an exception, but I wouldn't bet on it.

[pyre]

The US doesn't need a 'secret warrant' to ask for information from another country. They don't really need a warrant at all. They just ask for it. IIRC, even the NSA isn't legally bound to avoid spying on American citizens when they are out of the country.

[mpyne]

To avoid it, no. But if they do uncover evidence on American citizens it could not be used in a trial and must be filtered out (although, see 'parallel construction').