Phones shouldn't have an expectation of privacy if they're over analog lines as you have no control over the content once it leaves you. I, personally, think that they're both overreach but, legally, I think it's the difference between someone listening to a conversation you're having in a public park vs. one that you're having in your bedroom at home. If someone can hear me in a public park, that's on me as I clearly didn't put thought into how accessible I was. If someone can hear me in my bedroom, though, then I have to question the integrity of my home.
Encryption was specifically created to guarantee the integrity of an A->B interaction. If we're compelled to break that, then the whole system is no longer able to be trusted and its integrity is shot.
Of course not phones! I mean, "The President's Analyst" ;)
But from a professional, and WWII hero:
> 17. The greatest material curse to the profession, despite all its advantages, is undoubtedly the telephone. It is a constant source of temptation to slackness. And even if you do not use it carelessly yourself, the other fellow, very often will, so in any case, warn him. Always act on the principle that every conversation is listened to, that a call may always give the enemy a line. Naturally, always unplug during confidential conversations. Even better is it to have no phone in your room, or else have it in a box or cupboard.
Maybe not naive but I think never trusting your own home is just a recipe for paranoia. You have no reason not to trust your home unless some actor had reason to do so from the onset. It's not a trivial matter to bug someone's home or bedroom without their detection unless you have free and clear access.
Edit: Just now realizing that you meant we shouldn't trust encryption and phones, not our home. Whoops. Leaving my response for posterity and lulz.
Spies meet in person because they're people of interest. They take the job knowing that nothing they do is ever really done in secret.
Encryption was specifically created to guarantee the integrity of an A->B interaction. If we're compelled to break that, then the whole system is no longer able to be trusted and its integrity is shot.