And that's at the heart of all these problems. People are vicious, especially when they're in large groups making decisions that they don't need to feel even remotely accountable for. Oddly enough, I'm not trying to make a small-government or anti-democracy point in general: this is probably the least vicious we as a species have managed to make ourselves behave.
Or to be more exact it's very hard for a DA to be elected when they appear to be lenient on crime.
The prosecution and the policing parts of the criminal justice system can quite easily be influenced through the popular vote.