At least as of a few years ago, AT&T still owned most of the core network in the US and leased it out to other ISPs. The government has a direct pipe into AT&T

At least as of a few years ago, AT&T still owned most of the core network in the US and leased it out to other ISPs. The government has a direct pipe into AT&T which allowed (still does?) them to sniff everything regardless of ISP since AT&T almost certainly owned the underlying pipe.