The US government isn't going to protect the public against crime. They can't.

The US government is a paper-pushing processor who will collect the crime documents after-the-fact and report it. They are not a preventative resource.

Technically, Society is the preventative resource. We, among ourselves, are responsible for our own behavior and to be good citizens.

So calling the cops isn't to prevent a crime, it's to report a crime, right? Scramble that for a moment.