Comment by lxgr

> they get automatically flagged as scams, because the dialer companies that the politicians use

If it were possible to reliably determine the source of a call in the US phone network, spam wouldn't be an issue!

Theoretically, STIR/SHAKEN should enable that; practically, there are too many gaps to enforce it (importantly, it does not travel across TDM, i.e. non-VoIP, paths), so spammers still get away with it.