We allowed the government to open mail, open locks and tap phones with a warrant all of which were technically challenging.
Phone networks must be set up with specific dedicated access for law enforcement heck I remember crawling through the SNMP MIBs on my Motorola cable modem 15 years ago and discovering a whole class of them dedicated to lawful interception.
Most networking equipment providers even have guides on how to set these up: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/sec_usr_cf...
And this is why the encryption battle is a bit odd to me as much as I would like encryption to be never tampered with we’ve already as a society agreed that the government in some cases should have access so what makes WhatsApp so different to a phone call?
If encryption isn’t a way to backdoor ourselves out of the existing legal interception laws then as much as I hate to admit it we don’t have a leg to stand on.
If it is then we should just publicly say that the government shouldn’t be able to tap phones regardless of what technology they are using to communicate.