At best police do one this passably well, investigate crimes that have already taken place. They don't protect the population at all. Police write reports on something that took place before they could get there. The only true answer to crime is to arm every citizen. The founders were all armed and presumed that following generations would follow suit.
Give some thought to this very real argument, "When seconds count, cops are only minutes away."
We the people, ordinary citizens, are responsible for our safety and protection. The Government will never be able to do that for you.