"FALSEHOOD flies, and truth comes limping after it," wrote Jonathan Swift, "so that when men come to be undeceived, it is too late; the jest is over, and the tale hath had its effect."
Surely Ryan Lanza, the brother of Adam Lanza, who committed a massacre on Dec. 14 in Newtown, Conn., would agree with Swift.
Ryan was miles away, minding his own business, when the media, including The Post, named him as the author of the bloodbath - and for the next few hours he was no longer an anonymous office toiler but a notorious mass murderer.
Yes, the truth finally limped along later. Still, the false accusation compounded Ryan's agony at learning that his younger brother used his mother's gun to kill her, 20 children, six additional adults and, finally, himself.
Many say we need a post-Newtown "national conversation" about gun violence. We do.
While we're at it, let's soul-search about the fact that the instantaneous spread of misinformation after mass killings is becoming almost as frequent as the massacres. And some of our leading media institutions are culpable.
On Jan. 8, 2011, NPR and others mistakenly reported that Rep. Gabrielle Giffords had been killed in a shooting rampage that did claim six lives.
On July 20, 2012, Brian Ross of ABC suggested that the shooter in the Aurora movie theater massacre belonged to the Colorado tea party; Ross had confused the actual killer, James Holmes, with another person of that name who popped up on an Internet search.
Initial reporting on the Dec. 11 shooting at a Portland, Ore., shopping mall included inflated body counts, inaccurate descriptions of the suspect and bogus rumors of multiple gunmen.
Something has to be done about this problem, too.
Calling for restraint on the flow of information - even, perhaps, self-restraint - might make me as popular with my media brethren as a gun control advocate in the National Rifle Association.
Like gun enthusiasts, we journalists have our very own section in the Bill of Rights, the First Amendment. And, not unlike the Second Amendment crowd, we tend to view complaints about misuse and abuse of our favorite freedom as a threat to it.
Reporters can also claim, quite legitimately, that we rush to correct our errors, which are often the errors of our sources, passed on by us in good faith.
Certainly those defenses are available to media that named Ryan Lanza as the Newtown shooter; the story was corrected later, and it did indeed originate with law enforcement.