I honestly don't see how contracting out your domestic spying to a foreign country makes it legal in the face of a law restricting such surveillance. For example, if the local police want to search your house, they need to go to court first for a warrant. They can't just hire a 3rd party to break into your house and then try to use that evidence against you. (the 'government agent' doctrine)
Then again, if judges continue to refuse plaintiffs who challenge these practices, then it really doesn't matter what the law is.
You're right from a 'getting a case in court' stand point, but I don't think most of the spying/tracking is about getting a case to court, and as the SilkRoad trial MIGHT have shown, the gov't just needs a way to show that they were able to track you down. They can probably make up a way that they did it after the fact if their initial search was in fact illegal.
Please don't turn this into a debate about SilkRoad, I'm using that as an example of something that might have happened, I'm not saying it did or didn't. That is for other threads.
Well, there's that whole FISA secret court thing. There's basically a body of law that's above the law in the U.S.. As a Canadian, I expect there's something similar here too. These courts ostensibly aren't interested in prosecuting people for the usual crimes like murder, drug dealing, etc.. Just the nasty terrorist-type stuff that will get just about any bill, no matter how abusable, passed by the powers that be. Of course, there's always mission creep.
Then again, if judges continue to refuse plaintiffs who challenge these practices, then it really doesn't matter what the law is.