In the pre-9/11 era, one way of protecting domestic citizens against secret-police style spying was a literal hard firewall between the legally domestic FBI and legally international CIA.
Also, police agencies tend to be fiercely territorial about their jurisdiction and this rivalry was no exception.
Historically, CIA was supposed to be doing international intelligence gathering things while the FBI was more along the lines of the federal government's domestic crime investigation unit. CIA never really had to care about privacy rights because their targets were practically always foreign nationals not protected by the US Constitution. The FBI was almost exclusively operating domestically where Constitutional rights are practically always in effect.
Just putting a note here that whether or not foreign nationals are subject to the protections of the Constitution is a contentious issue.
IANAL, but in many places the Constitution specifically calls out citizens vs non-citizens and in other places does not make an explicit distinction. The bill of rights is one place it doesn't explicitly specify, and indeed uses language that elsewhere was used to indicate it applying to citizens and non-citizens. Of course that interpretation fell away during the cold war and is less popular now.
> The Patriot Act was written with “sunset” provisions requiring Congress to re-authorize the program every few years. Although the Act expired in March, 2020 without being reauthorized, federal law enforcement agencies retain most of the authorities granted by the act. The surveillance infrastructure that the Patriot Act created exists to this day. The Patriot Act is a prominent example of the use of terrorism to justify expanding government surveillance.
> Although the Act expired in March, 2020 without being reauthorized, federal law enforcement agencies retain most of the authorities granted by the act.
By what statute do they maintain those authorities if the authorizing legislation has expired?
It looks like those were sections 206 and 215, which were somewhat weakened by the same act.
Confusingly, there's a third provision, the "lone wolf" provision, which was extended during the Obama administration; that seems to be part of the Intelligence Reform and Terrorism Prevention Act of 2004 and got rolled into the "USA Freedom Act" reauthorization in 2015.
You will note that US companies are still effectively, theoretically banned in the EU because violating fundamental human rights of persons located in the EU - and will likely still be as long as the Patriot Act-like laws, the NSA, or the EU still exist :
See the second link above (added after your comment, sorry.)