Update January 8, 2020 Law now signed that will require phone companies to develop ways to detect and combat illegal robocalls and malicious caller ID spoofing and allow them to block those robocalls before they reach consumers.
Published June, 2019
Update June 12, 2019 The FCC now allows telephone providers the ability to block all robocalls by default to your number unless you specifically opt out of this service. They are urging phone companies to verify calls and then block ones that don't originate using a legitimate number.
The Federal Communications Commission (FCC) is offering a proposal that in essence allows phone companies to block unwanted calls to their customers by default, resulting in a legal shield for blocking certain calls. If it goes through then much of the legal liability that telephone companies could now face would be removed. Under the proposal, according to FCC Chairman Ajit Pai, it could be a comparable method to the way email providers filter messages into spam folders. The FCC wants to motivate telephone companies to use SHAKEN/STIR, an authentication framework method for blocking unwanted calls. SHAKEN/STIR (Signature-based Handling of Asserted information using toKENs) offers a way to make sure the phone number the call is coming from is actually the correct number and not one that is spoofed. A major trade group that represents telecommunications providers, USTelecom, has already praised the proposal.