The above quote was made by Henry L. Stimson, Secretary of State, in regards to diplomatic correspondence and the reading of it, by the United States, in 1929. Depending upon your point of view, Stimson's attitude was either one of courageous insight which upheld the rights and the concept that diplomatic communications of nations that we were not at war with should not be intercepted and decoded, or just plain stupid naiveté of a sleuthing amateur, far outside his element, and lacking in the basic knowledge that information is power, no matter how that information is obtained.
Those spying days are generations removed from where we are today in regards to intercepting communications both domestic as well as foreign, and our ability to decode, process, along with our skill in correlating information today is unparalleled. While there is definitely controversy about spying in America, most of that controversy nowadays is directed more towards the protection of our own citizen's 4th Amendment rights which are meant to secure us against unreasonable searches, rather than being concerned whatsoever about spying on enemies or allies.
The thing is, if you do truly believe that it's just fine to spy on other governments as well as other country's citizens, whether they are allied with your country or not, it sure doesn't take much more effort to move the needle a little bit further over to authorize that the government should also have the right to spy domestically because we can't trust certain people from certain countries that are within our borders, nor can we trust their friends, or their friends of their friends, or associates, or their visitors, or sympathizers, or people that are in the same vicinity, or go to the same functions, or share some common link with those people, until after connecting all the dots, and all the degrees of the dots, you pretty much come to the conclusion, that the government has to track everybody, all of the time.
If you then still believe that all of this is right and good, and in fact, is patriotic in some way, than it isn't too much further of a stretch to stipulate, that the government should have the right to especially track, harass, arrest, and/or punish people that through analytical analysis are more likely than others to be a potential enemy to the State as it exists today. This is the path that we are currently on, a country that treats its citizens separately and unequally without fairness or justice.
Do we really need to read each other's mail? Do we really need to know all the minutiae of everybody? The government insists that we do for our own protection and for our security, but that's simply the excuse that they use in order to more effectively monitor and to control its own citizenry. The government wants to have all of this information on all of us to ensure that they have the means to suppress and to control us. So far, it's working quite well for the government, while there are always going to be a few outliers, many more are content just as long as they continue to reliably receive their bread and their circuses.