> the government if they serve the cell phone company with a warrant or other legal proceedings

The police may have to sometimes jump though a couple of rubber stamped hoops, or hand over stacks of taxpayer money to companies for access to their online law enforcement portals, but the government is already inside taking everything that passes through those companies, using hardware those companies have been forced to install and/or by the outright seizure and occupation of their private property. There's nothing constitutional about it, but this has been true for a very long time (https://en.wikipedia.org/wiki/Room_641A) and it's not going to change.