I'll begin. Certainly, within the system, our ability as a country to deal with organized crime, violent street gang crime, etc., relies on our justice system. Our justice system won't work unless we have people who are willing to testify against offenders.
We all know of cases across the country where people have been reluctant to testify because they fear for their safety. We need the capability to protect witnesses who come forward to testify in order for us to gain convictions against dangerous offenders who need to be kept off the street. Our system isn't going to work without it.