They do far more than that.Like...?
Like compiling records and information on all sorts of people who are opposed to whatever the current war/crisis happens to be.
When I was in the Army, working with the NSA and all sorts of other alphabet agencies, I saw a book the size of a big city phone book with the names and bios of thousands of American citizens. Reading through it, it was clear that many of them were activists against the Vietnam War - although there were far too many of them even for that. (Unless you assumed that there were several thousand significant antiwar activists.) It was stamped Top Secret - Eyes Only. It was apparently compiled by the NSA, in conjunction with their military counterparts. The minute I saw it I knew it was a violation of law. The fact that I saw it on Okinawa told me that it almost certainly wasn't the only such book in existence. They had no real use for it in Okinawa.
As I have said many times, this kind of snooping - far beyond what most people here imagine - has been around for at least forty years that I know of. I have seen it myself. In general, they collect whatever information they want to collect and, from what I can see, there is no effective way to stop them.
Did you ever hear of the Pueblo incident where a US spy ship was seized off North Korea in 1968? Got any idea what it was doing before it was seized? Among other things, it was listening to phone calls carried over ordinary land lines several miles inland -- from international waters. That was before the days of computers and high technology. Imagine what they could probably do now.
Someone is worried about the NSA monitoring international phone calls???? Come into the real world. I would bet with the state of the art now, there are any number of ordinary clerks who can type something into the computer and listen to any phone conversation in the country -- with or without official approval and without any oversight.