"secure comms are the point at which people move from curious innocents to national security risks"
False argument. The US Constitution, if it were still respected, is that point.
"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."
This Amendment does not care if unreasonable searches are conducted via electronic surveillance or by goose-stepping through the house. Neither are permitted. The Constitution says you need a warrant to invade a suspect's privacy, period.
Why this point is not driven home with a bat sledgehammer is beyond me.