As a former NSA agent I can tell you, the answer is, it depends on who you are!
I worked at the NSA as an Arabic linguist for four years after 9/11, during which time I was awarded the Global War on Terrorism Civilian Service Medal for time working in Iraq in 2004.
So, I was very much encouraged and tasked to spy on known Al-Qaeda targets. (ISIS didn’t event exist when I was there!). I was trained in target development and got pretty good at finding new bad guys to follow based on their contacts with earlier known bad guys.
Now, I have a lifetime responsibility to not divulge any classified information that I learned while I was there. And both from a desire to not compromise our ongoing intelligence operations and also not go to jail, I abide by that and take it seriously.
And so, in an unclassified manner, here’s what I can tell you happens when an NSA agent decides to spy on you.
1) They very probably don’t even have the ability to spy on you.
You think the NSA is set up such that every agent can just press a flurry of keys on their computer and now they are spying on their intended target? Not even close.
A typical team at the NSA has people who do, for instance, what I did–translate intercepted communications in a target language (in my case Arabic). They have other people who are expert in taking the translated materials and forming them into an intelligence report, which they can indeed send, with the click of a button, to places like the White House. And that team also has people specifically devoted to tasking new targets developed in collaboration with the linguists.
But only a few people on the team can “task” those new targets. “Task” means “start spying on.”
2) The Department of Justice and Congressional Oversight Committees are Notified Immediately that the NSA is Spying on You.
That’s right. Every single time something is “tasked,” it is automatically logged and sent to multiple outside oversight bodies to assess whether this is indeed a legitimate NSA target.
And to give you an idea of what would happen if someone inappropriately “tasked” something that was not legitimate, back in 2011, a Naval Officer assigned to an NSA facility in Iraq very inappropriately tasked a phone number associated with the son of her boyfriend back in the US. Apparently this person was wrongly given more access to tasking than would be typical back at NSA HQ at Fort Meade.
If you read the NSA Report on the matter, you will immediately see that this was treated as extraordinarily serious upon detection. The offending individual was immediately removed from any contact with classified materials and disciplined.
Here’s the point. This was detected and dealt with because the NSA really does have strong measures in place to prevent any abusive interception of US citizens’ communications.
So, in answer to my original question, what happens when an NSA agent decides to spy on you?
If you are a legitimate intelligence target of interest to the security needs of the United States, hopefully your communications are now going to be monitored by talented linguists who will process what you say and report it to tactical, strategic, and policy players of the US Government.
If you are not a legitimate intelligence target of interest to the security needs of the United States, you are not going to be tasked. Period.
And if you are, it is not going to be done by some random agent inside. It is going to be done by your girlfriend who works at the NSA. And your (former) girlfriend is going to be fired and maybe go to jail shortly thereafter.
Either way, you very probably have nothing to fear from NSA surveillance.