Earlier quoted context omitted.
Want mathematical assurance that your government won't abuse power against you? Either you have to be the government or you don't live in a society with a government. Abuse isn't so easily constrained. Try proactive regulations, vigilance, and strict punishments (not comprehensive). Best effort, but what else can you do?
"Government can never abuse power or government can systemically abuse power" is a false dichotomy. You can make it cost more so it happens less. Encryption is the common example. As far as anybody knows the government can't break e.g. AES. But they can still find out what's on your device because with a warrant they can install surveillance devices in your house to capture it when you enter your passphrase, then sei…
I didn't make it a dichotomy. I was just commenting that "mathematically impossible" is too strong to the point of absurdity. Not fun at parties, but I would hope it's fine on Hacker News. I then provided a rough overview of a system to mitigate abuse. We're not even disagreeing about trying to minimize government abuse.
To discuss your example of encryption, the abuse is the government installing and using the surveillance devices (let's assume the suspicion isn't beyond reasonable doubt or whatever and the warrant is invalid). The question is whether that abuse is prevented or routed and justice is enacted.