[trhway]

That agreement is to not to spy on each other against each other's will. That is completely different from spying on each other's domestic targets at each other's request/will to workaround domestic no spying and privacy protections laws.

[wbl]

Explain how anyone would think that works. You can't get around the 4th amendment by directing someone else to violate it.

[trhway]

UK spying on US citizens doesn't violate US Constitution and the 4th in particular which naturally applies only to US government and the people on US soil. And thus they do it that way. UK obviously has all the rights to listen, record, etc on telecommunications of all of the foreigners, including US people on US soil as long as the traffic leaves the US (and even if not - i don't think they bother to pay attention to such a small detail as long as they are doing it from comfortable office in London :).

>Explain how anyone would think that works.

US government lawyers explained how torture is legal. Compare to that, the circumventing of the 4th by means of allies doing the actual spying ... i'd be surprised if they even bothered to explain it away.