"Legally" is dubious. Intercepting any private wire communication is a clear violation of federal law (e.g. 18 U.S. Code § 2511), and a violation of the law in

"Legally" is dubious. Intercepting any private wire communication is a clear violation of federal law (e.g. 18 U.S. Code § 2511), and a violation of the law in many states (e.g. CA PC 631). Unfortunately, the US government is one of the larger users of ISP surveillance activities, benefiting through the purchase of private data as well as using administrative subpoena to obtain the data collected by ISPs without due process or meaningful oversight. This creates a conflict of interest which I believe is preventing the US from zealously enforcing existing criminal law which would be otherwise sufficient to significantly reduce surveillance by communications providers.