The Supreme Court has ruled that individual communities must use a jury trial to determine whether pornographic material violates obscenity standards. It's a difficult test because no one really knows whether a crime has been committed until the verdict is delivered. Nevertheless, it's been the system for the past 35 years and has allowed many communities to get rid of hardcore pornography.
The system breaks down, however, when law enforcement agencies at the state, local, or federal level do not enforce obscenity laws. If a business suspected of violating the law is not investigated, cases cannot be brought to trial. If cases don't go to trial, a community has no opportunity to exercise its constitutional right to determine its own standards.
The absence of effective enforcement favors criminals and lowers community standards, because material is presumed to be legal unless proved otherwise in a court of law. What we see across the nation today are communities held hostage by pornographers and by reluctant law agencies ignoring the needs of those they have sworn to serve.