>>507923039the TLDR answer is they have different purposes. The NSA almost exclusively collects signals intelligence and has jurisdiction over signals intelligence activities, the CIA collects human intelligence and has jurisdiction over human intelligence activities. While they may do other things, the primary function of the CIA is to interrogate, conduct source operations, and conduct covert or clandestine operations in foreign countries. The NSA is tasked with collecting all signals, but to actually review the massive interception information or conduct targeted surveillance on US persons requires a lot of authorization and a pretty high bar when it comes to justification... however, there are plenty of intelligence agencies which are specifically tasked with domestic issues, but they dont get any where near the same criticism because they never had an Edward Snowden, and they haven't been around long enough to have had documents declassified like the CIA has.
You're welcome for this insight, because I already know im going to get called a fed though this is the actual truth of the matter