I would argue that the unrealistic stance to take is that spying is necessary - let me ask you this: why is surveillance necessary? why do you need foreign intelligence?
Are you worried about an invading army showing up on your shores tomorrow? who? You don't think you'd detect them with your radars, sonars, satellites, etc?
Maybe you need to spy so that you can get the competitive edge in business - you know, get mcdonalds into antarctica and secure those lucrative jet fighter contracts for boeing. You don't think that the US and US companies could just get along by playing fair with everyone else? You don't have a reputation for superior engineering and good manufacturing - you need to play dirty to survive? Having a reputation as "the country that always plays fair" wouldn't be worth anything at all in financial terms?
Aha, I've got it! you're worried about a sudden nuclear attack - those pesky french could always nuke Washington tomorrow, so you need to spy! You don't think that making a noble gesture like proposing a total blanket ban on nuclear weapons worldwide and offering to completely dismantle your stockpile would help relieve tensions? You really think the North Koreans would bother nuking you if you dismantled your entire stockpile? I think you'd find they just might dismantle theirs and start feeding their people a little better or risk revolution when the amazing and unprecedented news that the US just disarmed gets through to the people. Of course we'd need to send in weapons inspectors to make sure that you weren't being sneaky.
Oh, I know - it's the same answer as everything else - you're worried about terrorists killing thousands of your civillians!
Assuming that this is a real threat (something of which I've seen absolutely no evidence ever), has it not occurred to you that there might be other ways of addressing the issue that don't involve taking morally repugnant actions?
Maybe you could ask them "why do you hate our freedom?" and they'll explain that it's not your freedom they hate, it's the fact that you aid their enemies and topple their governments so that you can get cheap oil. If you guys stopped being assholes, this "problem" would go away all by itself. A great way to start having this conversation would be to start talking about redressing crimes committed by previous administrations - the terrorist threat you foam at the mouth about would lose a metric fucktonne of momentum overnight if you'd charge dubya for the war crimes he committed, for example. "Terrorist problem" solved, zero new evil done.
History does not suggest that we cannot better ourselves.