When in the world are the conspiracy theorists among us going to stop fishing for a quarry that they cannot ever catch?

Or … put another way: When will they stop looking for a second gunman who took part in President Kennedy’s murder nearly 60 years ago in downtown Dallas?

A new book by a former Secret Service agent now proclaims to have evidence of a “magic bullet” that he found in the president’s limousine. Sigh …

Paul Mathis was on duty that day in Dallas and has written an account of what happened.

As the Dallas Morning News said in an editorial published this morning: The investigation that led to the much-criticized Warren Report speculated that the bullet in question passed through Kennedy’s neck, then pierced Texas Gov. John Connally’s back, exited his chest, and also wounded his wrist and thigh. The theory was partly informed by the fact that the bullet was found on a stretcher that may have been the one holding Connally at Parkland Memorial Hospital later that day. The theory held that the bullet came to rest in Connally’s body or clothing after its miraculous journey, and fell out as he was being treated on the stretcher.

I do not believe in conspiracies. Especially not anything related to this dark and horrible incident. I have long believed that Lee Harvey Oswald was capable — given his military training — of firing three bullets from a rifle while sitting on the sixth floor of the School Book Depository building on Nov. 22, 1963. I also believe he was capable of hitting the president with a fatal rifle shot.

What’s more, I also know that bullets do strange and unexplainable things once they pass through human tissue.

Whatever. These conspiracy theories will live long past all of us who are alive today. As the Morning News noted in its editorial: But in 60 years, no tantalizing detail has managed to provide reliable evidence of a conspiracy or a second gunman. None likely ever will.