This is the way things have worked since the United States was formed and is written into the Constitution. Do you actually think the justice system should not have the ability to use warrants? Then you need to change the Constitution.
As I said: What if corrupt, evil, law enforcement working with corrupt, evil, judges are able to issue warrants and read whatever they want, whenever they want?
I think the problem I see is in there somewhere. Did I state it poorly? How could I state it better?
The point is they already can. You're proposing to change the status quo in every functioning government on the planet. Since these people are ultimately controlled by the voters, they are ultimately acting to fulfill the will of the voters.
No, they can't, at least that's what they're telling us. Some devices, they haven't been able to get into. That is the status quo. Being able to crack properly done, effectively unbreakable encryption is not the status quo, it's a fantasy.
And voting? You are assuming democracy. Also you're forgetting about the tyranny of the majority. If you aren't even going to read what I'm saying, let's just stop here.
Agreeing with other comments, that seems like a problem with warrants in general, not with some supposed technology. If cops can get a warrant to raid anyone's house then of course they'd be able to get a warrant to raid anyone's phone in this situation. The solution to that issue would be to fix how warrants are granted to make them less prone to abuse. But that seems like an entirely different debate.