Saul Cornell, who is a professor of history when he is not writing for Slate, is engaged in intellectual dishonesty. He claims, as I note below, that a 1964 study of firearms lethality says something that it does not say (and, indeed, that it could not say, given its date of publication) in the course of trying to make modern sporting rifles sound scary for cheap propaganda purposes. Saul Cornell knows that this is false, and I know that he knows this is false, because I have told him, and he has acknowledged the fact in emails to me. But the claim remains unretracted. Retracting the claim would mean admitting that the source he cites not only does not say what he says it says about AR-style rifles, but that it in fact does not say anything about those rifles at all.
Honest mistakes happen all the time in journalism. This is not one of those. This is a fabrication.