There’s a pretty good movie about vigilantism called “The Star Chamber,” starring an impossibly young Michael Douglas.
Briefly it’s about a group of judges who are sick and tired of seeing criminals get away on technicalities, therefore they hold their own secret trails, pass sentences and carry them out. Meaning these judges hunt down the people they deem to be guilty and kill them. What happens when they go after an innocent man? Worht checking out.
A court of law provides the opportunity to prove a man guilty. This provides the moral sanction needed to impose a sentence on the convicted. If a citizen can take the law into his hands, with total disregard fro standards of proof, what’s to stop government from doing the same thing?
As part of the separation of powers the police, a part of the executive branch, have a role very different from that of the courts, part of the judicial branch, or the legislature, the legislative branch. A cop can aprehend a suspect, question him under certain conditions, investigate him under certain restrictions, and gather evidence again under restrictions. He cannot execute a suspect, jail him, confiscate his money or property, or even restrict his movements in any way. But if taking the law into one’s hands is justified for a private citizen, why not for a cop who knows John Doe is guilty but can’t prove it? Why can’t a mayor, a governor, a president, or for that matter a congressman, a senator, or a judge or a DA order the police to execute a suspect any time they think they have a criminal who might get away? Or simply to spare the victims the agony of a trial, or to save the court time and money?
If an exception can be made, it would be only when the system breaks down and provides no help at all to a citizen who’s rights are being violated. I don’t mean that the police and courts cannot put away a criminal, but more as if they don’t even try. Suppose, and it’s not much of a supossition in some places, that police were to ignore any crimes against a group largely disliked by the general population (gays, blacks, immigrants, Irish, former criminals, defense attorneys, lawyers in general, people fo the wrong religion, etc); such things have happened in various palces at various times.
Then, yes, there would be a moral right to take justice into one’s hand. But doing so would also likely be suicidal. Imagine a free black man in the South in the 1860s whose wife was raped by a white man. You can safely assume the police would do nothing about it. If the agrieved man, rightly, then seeks out retribution, even something short of murder, what do you think the police would do?