You can stop 100% of crimes with a 100% effective law enforcement mechanism. The term for that is authoritarian dystopia.
Our ancestors recognised this a long time ago, and recognised that there's an intrinsic balance between individual freedoms and the degree to which laws are enforced. We are shifting hard and fast to the extreme authoritarian end of that scale.
There's nothing impossible about it. It's merely a question of resources. Pervasive surveillance+ML coupled with an implanted device which incapacitates an individual would get you there. Fast forward to an Elon Musk future where everyone has a neural lace, feeding their every thought and intent to pervasive surveillance. Futuristic? Sure. But not far off and certainly not impossible.
Of course it is. I could be perfectly normal and ok, you invite me to dinner, we sit down, I don't like the way you prepared the potatoes, take my fork and stab you without any warning at all. Even if you survive a crime has been committed.
Morality based on external pressures is never sufficient -- an environment where personal responsibility and individual liberties are abrogated in favor of absolute totalitarianism is an environment where violence and criminality can flourish without hesitation.
No, it's not a balance between our rights and law enforcement; it's laws and law enforcement that stop where our rights begin. A "balance" inevitably ends with all law, all enforcement, and no rights.
