Crusader in D&D pointed out this isn’t the first time something like this has happened. The story of Project SHAMROCK is pretty interesting.
Project SHAMROCK, considered to be the sister project for Project MINARET, was an espionage exercise that involved the accumulation of all telegraphic data entering into or exiting from the United States. The Armed Forces Security Agency (AFSA) and its successor NSA were given direct access to daily microfilm copies of all incoming, outgoing, and transiting telegraphs via the Western Union and its associates RCA and ITT. Operation Shamrock lasted well into the 1960s when computerized operations (HARVEST) made it possible to search for keywords rather than read through all communications.
The is testimony from those involved with the original investigation up on the CIA homepage, definitely worth the read.
From L. Britt Snider: Recollections from the Church Committee’s Investigation of NSA
We sought pertinent documents and witnesses from each of the three companies involved: RCA Global, ITT World Communications, and Western Union International. No one could find any record whatsoever of an agreement with NSA or ASA setting forth the terms of the operation. Only RCA Global could produce a witness who had been involved in establishing the arrangement after World War II; the other two companies could produce a few witnesses– mid-level executives–who had become aware of the arrangement over the course of its existence. I deposed each of the witnesses the companies identified.
The RCA Global executive, then retired, was the most colorful and forthright of the lot. He offered no apologies for what he or the company had done. He said the Army had come to him and asked for the company’s cooperation, and, by damn, that was enough for him.
The executive from ITT World Communications, by comparison, came to the deposition surrounded by a phalanx of corporate lawyers who proceeded to object to every question I asked once I had gotten past the man’s name and position. I pointed out to them that this was the United States Senate–not a court of law– and, if they wanted to object to the questions I was asking, I would have a Senator come in and overrule every one of their objections. They piped down after that and allowed the witness to respond to my questions.
The executive from Western Union International gave a slightly different version of the operation. He said that in his company, employees would microfilm copies of outgoing international telegrams that would then be picked up by a government courier.
All the company witnesses testified that their companies had assumed NSA was using the telegraph traffic only for foreign intelligence purposes. It did not occur to any of them that NSA might have used their access to look for the international telegrams of American citizens, nor were they aware that their companies had ever sought assurances from NSA on this point. Moreover, all were adamant that their companies had never received any compensation or favoritism from the government in return for their cooperation.