Here's a contrarian view. I would argue that mutual spying in general is a good thing and that it generally has the potential, properly managed, to prevent war

Here's a contrarian view. I would argue that mutual spying in general is a good thing and that it generally has the potential, properly managed, to prevent war. The problem has to do with leadership and less to do with spying itself. During the cold war, both the US and USSR had extensive satellites deployed that would provide an early warning for the launch of ICBM's. As Lt. Robert Bowman pointed out in "Star Wars: A Defense Expert's Case Against the Strategic Defense Initiative," this had a stabilizing effect because both sides could be certain they were not being attacked and therefore would not be inclined to mistakenly counter-attack. Spying can have a similar effect in that it can provide additional reason to believe that another party is not in the process of preparing an attack. The larger problem though is that geopolitics is real. We didn't invade Iraq for the reasons we were told. We did it for geopolitical and domestic political reasons, and every piece of data would be tortured enough that it would say what the government wanted it to say, even if no reasonable person could put all the data together and make it say what Bush wanted it to say. In this area then spying is beside the point. We shouldn't forget that the CIA exists to offer a counterbalance to military intelligence which is more likely to rattle sabres than a civilian agency.