The legal concept of the public nuisance has for long been recognized throughout all the civilized countries of the world. Basically, and unadorned by the tortured language of the legal profession, a public nuisance is one who uses property to annoy or damage an individual or the general public. Occasionally, the annoyance or damage is sufficiently grievous for the public nuisance to suffer some sort of penalty.

Starting at some point in the last century, the public nuisance acquired a halo by claiming that his obnoxious behavior was induced by high purpose and noble values. In the 1930s, pacifists tested the outer limits of public nuisance law to oppose America’s entry into World War II. Adolf Hitler and Benito Mussolini favored their labors – to a point. In the 1930s, there were also food fanatics and nudists numbered among the public nuisances. Through the years, Americans have become inured to these misfits and malcontents, sympathetic as we are to the protesters’ claims to higher virtue and noble purpose.

By the later decades of the 20th century, many public nuisances’ misbehavior moved from mere mischief to mayhem, but ordinary Americans have remained good natured, generally, so long as the nuisances are not trampling the ordinary Americans’ petunias or hauling them into court. Nudists are too polite to commit such excesses, and even militant bicycle riders shun such tactics. Yet there are public nuisances who frequently engage in rough stuff. Probably the roughest of the public nuisances are the animal rights fanatics. Some actually undertake acts of terror, blowing up laboratories and – for some reason – ski resorts. Just a few months back, 11 were indicted on federal warrants for such crimes.

Other animal rights groups aim at intimidation, through noisy demonstrations and court action. People for the Ethical Treatment of Animals, or PETA, engages in this sort of thing. Yet it has recently been targeting entities that enjoy the sympathy of ordinary Americans, for instance, family entertainment groups such as the circus and laboratories where scientists endeavor to discover medications for greater health and less human suffering.

Demonstrating against a circus or a laboratory might sucker the weak-witted, but not sensible Americans, and recently, when the animal rights nuisances have dragged their victims into court, they have lost. The burden of proof that exists in an American courtroom is much higher than at one of the media events the animal rights nuisances stage.

On March 15, in the Ohio Supreme Court, an animal rights group’s effort to force Ohio State University to release animal testing records failed thumpingly. A couple of weeks earlier, a federal court in New Jersey convicted animal rights thugs for inciting violence in their effort to shut a medical research facility. Science triumphed over these reactionaries. Also in March, a northern Virginia jury exonerated the owner of Ringling Brothers’ circus from charges that he and company executives wiretapped PETA headquarters and stole PETA documents.

The Ringling Brothers case is significant because PETA has used the courts to harass the circus for years. In this case, the circus owner, Kenneth Feld, was willing to face PETA’s charges in court. Had PETA merely complained to the press, people might have believed that Mr. Feld maintained a vast spy ring against his harassers. In court, their evidence was dismissed as nonsense.

Actually, their whole case is nonsense. Circus animals are as highly prized by animal trainers as domestic pets are by their owners – perhaps more so. After all, the trainers’ livelihood depends on these animals. Cruelty toward animals exists, to be sure, but it is unlikely that trainers who spend their entire lives around animals would be cruel to them. More likely, such trainers have affection and even admiration for their animals, much as a hunter has affection and admiration for his hunting dog. Then too, it is unlikely a cruel trainer would be successful with his animals, and it is even unlikelier that a cruel trainer’s cruelty would go unnoticed in such a high profile position.

Every year for decades, ordinary Americans have taken their families to the circus. One wonders what PETA’s nuisances would suggest as a humane alternative for the children who thrill to the mighty elephants and the gigantic cats. How about suggesting that Ringling Brothers use artificial animals? Surely in this high-tech world, someone can come up with a robotic elephant. Or maybe just used stuffed animals. Children love their stuffed teddy bears. Yet I doubt such alternatives would soothe the folks at PETA. They are public nuisances, but the law is catching up with them.

Mr. Tyrrell is founder and editor in chief of The American Spectator, a contributing editor of The New York Sun, and an adjunct scholar at the Hudson Institute.