Breed Specific Legislation (BSL) is a set of public policy laws designed to improve public safety from dangerous and/or deadly dogs by focusing on specific breeds or groups of individual breeds.
BSL relies on the premise that all dogs of a certain breed-- or groups of breeds-- are dangerous/deadly. As a research paper by James H. Bandow of the National Center for Biotechnology Information points out, "Breed-specific legislation has three weaknesses: vagueness, over-inclusiveness and under-inclusiveness." (pp. 480)
In the past, BSL has targeted Chow-Chows, or German Shepherds, or Rottweilers. Now, the focus is on the vague "pit bulls". Pit Bull, like pointer, gundog, and retriever is not a breed, but a loose collection of breeds. The breeds include, but are not limited to, American Staffordshire Terrier, Staffordshire Terrier, English Bulldog. Some descriptions of the breed group include different specific breeds. This vagueness is part of the problem because laws which are vague are usually found unconstitutional because a person should be able to understand what is required of them so the person can strive to not run afoul of the law. Thus vagueness is a real problem with public policy.
Another identified problem with BSL is that is casts too wide a net. While nobody ignores the fact that there are, in fact, dangerous and/or deadly individual dogs presenting a public safety risk, it is unsound policy to assume that every individual dog of any breed presents such a risk. If that were the case, every "pit bull" type dog would bite and/or kill. This is clearly not the case. Over-inclusiveness causes the authorities in charge of enforcing the laws to waste resources rounding up, housing, and destroying friendly dogs simply because they fall into an arbitrary category.
The third problem identified was under-inclusiveness. By straining the local animal control agency's resources to the breaking point by focusing on all local dogs of a certain breed or group of breeds, no resources are left for dealing with dangerous individual dogs of other breeds and public education.
If the National Center for Biotechnology Information stood alone in their findings, then it could be argued that they were simply anoutlier. Nothing could be further from the truth, however. The Center for Disease Control also agrees with NCBI as shown here:
"Many practical alternatives to breed-specific policies exist and hold promise for preventing dog bites. For prevention ideas and model policies for control of dangerous dogs, please see the American Veterinary Medical Association (AVMA) Task Force on Canine Aggression and Human-Canine Interactions: A community approach to dog bite prevention."
Furthermore, many other groups of professionals and experts in this field hold BSLs, as public safety policy, in contempt. These groups are (in alphabetic order): American Dog Owners Association (ADOA); American Humane; American Kennel Club (AKC); American Society for the Prevention of Cruelty to Animals (ASPCA);American Veterinary Medical Association (AVMA); Association of Pet Dog Trainers (APDT); Humane Society of the United States (HSUS); International Association of Canine Professionals (IACP); National Animal Control Association (NACA); National Animal Interest Alliance (NAIA); National Association of Dog Obedience Instructors (NADOI).
Breed Specific Legislation is, plainly, bad public policy for a number of reasons.