Nearly 50 years ago in his “Complete Guide to Thoroughbred Racing,” the groundbreaking granddaddy of modern handicapping books, Tom Ainslie instructed readers to view with extreme skepticism any horse who had not raced in the last 14 days. Sharp and in-form horses should be racing at least that often, he said, and a quick runback was a sign of a thriving horse. Today in New York, Ainslie would never make a bet. Under a bizarre and ultimately cynical directive issued by the New York Racing Association last week, no horse will be allowed to race at Aqueduct more than once every 15 days. The measure is supposed to address safety concerns raised by a rash of breakdowns at the Aqueduct winter meeting. It is unlikely to do so, given that it is based on false assumptions and corporate image-crafting rather than any science or even common sense. It’s a good thing NYRA doesn’t host the Preakness: No horse who ran in the Kentucky Derby would be allowed to run 14 days later in the second leg of the Triple Crown. Woody Stephens would not have been allowed to win the Metropolitan Handicap on a Monday and the Belmont Stakes five days later with Conquistador Cielo. John Veitch could not have sent out Proud Truth to win the Discovery a week before taking the Breeders’ Cup Classic. But what do Hall of Fame horse trainers know about training horses, compared to a bureaucracy trying to claim credit for safer racing and then overreacting when the numbers turn against them? As a practical matter, the 15-day rule won’t accomplish a thing besides understandably angering owners and trainers, who are in effect being told they are irresponsible and courting disaster every time they run back a horse in 14 days or fewer. “Whoever made that rule has no idea about training horses,” trainer Mike Hushion said last week. As a symbolic matter, it is a terrible precedent that can only harm the sport by endorsing the falsehood that quick runbacks are inherently dangerous. It would be one thing if NYRA or anyone else had done a legitimate, comprehensive study proving that horses who run back within 15 days break down more often. But there is no such study because it isn’t true. In fact, research presented several years ago by The Jockey Club suggests the opposite: Horses who race early and often appear to gain bone strength and turn out to be sturdier. The most at-risk horses are not the sharp claimers running back on 10 days’ rest but the 5-year-old maidens making their belated debuts after years of physical problems. The 15-day rule does absolutely nothing to address the breakdown situation; you might as well hire a witch doctor to chant spells over a black candle at midnight. The rule sounds as if it might have something to do with safety, but all it really does is to anticipate the wrongheaded objections of the misinformed. The horses must be running too much, so let’s have them race less often! Look how much we care about safety! NYRA has generally done a commendable job of doing what it can to promote safety and equine welfare, instituting most of the recommendations of a state task force and taking the issue seriously. Unfortunately, it also has taken advantage of brief swings in the fatality numbers to congratulate itself for allegedly superior management, so now it is embarrassed and panicked when the numbers inevitably even out and start to trend the other way. The problem with taking credit for randomly good times is that you then have to offer an explanation for the randomly bad times. Whoever is telling NYRA to stake its claim to competency by counting casualties and blaming trainers is giving it very bad advice. Officials say fans should not worry about the 15-day rule messing up stakes races at Belmont and Saratoga because it is only a short-term measure, likely to disappear this spring. If so, that sends another curious message. If mandating 15-day rests is a lifesaving safety rule in February, why isn’t it the same in June? Either it is a good and necessary measure or it isn’t. It isn’t.