Are we done hyperventilating yet?
What is your expectation of privacy (yes folks, the 4th Amendment, the one we're all screaming about, goes to expectations of privacy) in the telephone numbers you're calling, or the numbers that are calling you? Not the conversation, the number, including time and date?
There is an answer, and it's not new.
In Katz v. US, the Supreme Court held that a wiretap, listening to your conversations, is a search, and requires a warrant.
Ten years later, in Smith v. Maryland, the Court considered pen registers. A pen register is applied in the phone company's central office, not in your home. The Court said:
we doubt that people in general entertain any actual expectation of privacy in the numbers they dial. All telephone users realize that they must "convey" phone numbers to the telephone company, since it is through telephone company switching equipment that their calls are completed. All subscribers realize, moreover, that the phone company has facilities for making permanent records of the numbers they dial, for they see a list of their long-distance (toll) calls on their monthly bills.
Finding no reasonable expectation of privacy, the Court found no need for a warrant to obtain this information.
In 1986 Congress passed the Pen Register Act, 18 U.S.C. § 3123(a)(1), which says the
court shall enter an ex parte order authorizing the installation and use of a pen register or trap and trace device anywhere within the United States, if the court finds that the attorney for the Government has certified to the court that the information likely to be obtained by such installation and use is relevant to an ongoing criminal investigation.
Even this is statutory, not constitutional. A later statute, say, the PATRIOT Act, trumps it.
Yes, it's creepy. But is the collection of numbers we call, information we voluntarily give to a private entity third party every time we do it, information we know the private third party is collecting because we see it in every bill, a violation of the Constitution? Nope. Is it even a new issue? Again, nope.