Because Americans gave up a lot of their rights, knowingly and unknowingly, after 9/11 to keep us "safe." Our Constitution and Bill of Rights are mostly just guidelines now. There's what happens in "public" vs what happens in "private," that you rarely hear about.
> On December 16, 2005, The New York Times reported that the Bush administration had been conducting surveillance against U.S. citizens without specific approval from the FISA court for each case since 2002.
> In 2011, the Obama administration secretly won permission from the Foreign Intelligence Surveillance Court to reverse restrictions on the National Security Agency's use of intercepted phone calls and e-mails, permitting the agency to search deliberately for Americans' communications in its massive databases. The searches take place under a surveillance program Congress authorized in 2008 under Section 702 of the Foreign Intelligence Surveillance Act.
> Because of the sensitive nature of its business, the court is a "secret court" – its hearings are closed to the public. While records of the proceedings are kept, they also are unavailable to the public, although copies of some records with classified information redacted have been made public. Due to the classified nature of its proceedings, usually only attorneys licensed to practice in front of the US government are permitted to appear before the court. Because of the nature of the matters heard before it, court hearings may need to take place at any time of day or night, weekdays or weekends; thus, at least one judge must be "on call" at all times to hear evidence and decide whether or not to issue a warrant.
I still think that it's funny how even something as third-worldy as a secret court wasn't enough. They didn't stop at disregarding the court system, they decided to make a joke out of the law itself. It makes you wonder what other laws the government sees as only suggestions. What credibility do the enforcers of the law have when they themselves only follow it when it suits them?
Without a warrant, most evidence (with complicated exceptions) can't be admitted into court, but can aid police in solving a case, then using "parallel construction" for court.
While relevant to the topic, I don't think this is responsive to the question. I.e., "why are police allowed to do this at all?" differs from "is it allowed in court?"
This touches on the idea of "poisoned fruit" or, more specifically, the "fruit of the poisonous tree". To quote Wikipedia:
> Fruit of the poisonous tree is a legal metaphor in the United States used to describe evidence that is obtained illegally. The logic of the terminology is that if the source (the "tree") of the evidence or evidence itself is tainted, then anything gained (the "fruit") from it is tainted as well.
The idea here being that the data obtained from hemisphere isn't considered "illegal" and, honestly, probably _would_ be permissible in court. The reason it's kept out seems to have more to do with optics than legalities.
So, I guess the simplest answer to the question of "why" is "there's nothing stopping them".
I disagree. I think it is kept out because it violates your 4th amendment rights, and if enough judges saw that violation at least one would remember their civic duty.
The information is owned by AT&T. They can be forced to hand it over to government warrant/subpoena. Or, they can choose to freely offer it (more likely sell it) to the government.
We can pass laws (and have such as with medical records) that even though the information is owned by <company> they can not use it/reveal it/etc because it is violation of privacy.
But we haven't done that.
Also, one thing many people don't remember is that the constitution/bill or rights restricts the government. It does not restrict private enterprises. Corporations are not required to protect your free speech, right to not be unlawfully searched, or any other right granted by the constitution.
