Amanda Bennett, the former editor of the Philadelphia Inquirer and Lexington Herald-Leader, is a freelance editor and writer.

So, dear Rolling Stone managing editor Will Dana , a month has passed since you published the dramatic, and now questioned, tale of gang rape at a fraternity at the University of Virginia. You have told us you are now reporting out the story to find out what really happened, and that you will tell us what you have found as soon as possible. And so you should. The brutal account that landed with such force deserves a thorough vetting. Unfortunately, as you now undoubtedly know, the time to do that was before you published, not afterward .

Everyone involved in that story — the fraternity, the campus, the unnamed (but since identified) alleged perpetrators and especially the victim — deserves a calm, dispassionate, evenhanded presentation of the facts of the evening in question, presented from all points of view. Do not rush this. Good investigative work rests on facts, and facts can be stubbornly hard to acquire. But once you get these facts and present them to us, your job is far from done.

For no matter what your investigation finds, you have done untold damage. You have done so by allowing a narrative to take control, by relying on what you have called “credibility” rather than facts to rule.

Allowing the narrative to take control is what crowds do. It is what mobs do. It is what despots and tyrants do. It is what, unchecked, we all will do. We believe the narrative that makes the best story. We believe the narrative that fits our point of view. We believe the narrative that underlies our fears. We will believe the narratives that allow us to feel good about our own actions and to demonize those who act differently.

There is nothing wrong with pursuing a strong story, or even with having a strong point of view. Advocacy demands it. And journalism, like science, is often at its best when pursuing a powerful thesis statement. A crime was committed here. An administration is corrupt. This system is unjust. There is nothing wrong with such advocacy journalism. The search for social change in a cause you believe in is an admirable pursuit.

But a strong narrative without the underpinning of facts is bias. And bias can morph in the blink of an eye into destruction, fear and suspicion. Look all around us for evidence of it from recent news events: All black men are threatening. All police are brutal. Our courts mete out justice. Our courts cannot be trusted. All Muslims are terrorists. All Christians are intolerant. All men are would-be rapists. All women are liars.

You, Will — as editor of a major publication with huge readership and huge credibility — had an obligation to do one thing well, and that was to find out what really happened. Everyone should do this before they make up their minds, forward a post, condemn an actor, a politician, a school, a system. For you, Will, whose publication commands so many resources and so much respect, that was your primary obligation. To temper the narrative with the truth. And it was to do so before you passed this story on to others.

Buying into a story, as your official statement says you did, based on your feelings that it is “credible” is buying into a narrative. And narrative ungirded by facts is bias. The most basic fact-checking involves reaching out to the other side. And that, you tell us, you did not require the reporter to do.

So, Will, if your temptation down the road is to seize on whatever facts your investigation uncovers to say: “See? We told you. We were right all along” — don’t. Just don’t. Instead, look at the harm that you have done by buying into the narrative and not checking the facts.

If it turns out that “Jackie” is a troubled young woman who has turned some trauma in her life into a gruesome fantasy tale, then you have committed the sin of exploitation. Deep, thorough reporting would have exposed the fault lines in the story and spared her and you. If your reporting finds that Jackie is credible and her story, despite inaccuracies in details, is largely accurate, then you have committed another sin by handing detractors of the issue the crowbars with which to pummel your — and her — account. No matter what you find, it is hard to imagine that you will ever restore the story to the credible status that you once believed it deserved. And that harms her, you and the cause you profess to believe in.

There remains a chance to pull some good out of this.

First you must resign. It was the job of the reporter and the editor on the story to get the facts. But it was your job to make sure they did — and that you could stand behind what you published. You did not do this. You must acknowledge this and step down.

Once you have resigned, you need to spend some time using your experience to help show everyone what happens when you believe the narrative you want to believe. Share your experience with Old Media. We can certainly use a refresher course. Share it with New Media. Spare younger journalists the pain of your experience. And share it with us all. We all need to hear this again and again.

For it is the decision to believe the narrative without checking that is made every day by anyone who forwards an Internet post without reading it. Who posts an outraged comment on a blog without stopping to think if the other side is true. You see the results of believing whatever narrative we want to believe in Ferguson, in New York, in Virginia, in Australia, in Pakistan.

Bias in support of a cause you love seems righteous. Bias in support of a cause you hate seems evil. Either way it is bias. And bias is so, so close to hatred.