Legal experts think PETA's suit seeking to define animal captivity as slavery is unlikely to succeed. But what if it does?

Last week, People for the Ethical Treatment of Animals once again made headlines — it's what they do — by filing suit in federal court on behalf of five orcas held in captivity by the SeaWorld theme parks, demanding their immediate release into a "habitat suited to their individual needs and best interests." (Orcas are the marine mammal often referred to as "killer whales," a moniker that advocates condemn as being a species-ist slur.)

What got media attention wasn't the suit itself, but its underlying complaint. Rather than claiming animal cruelty or neglect, PETA alleged that SeaWorld was guilty of violating the orcas' constitutional rights under the 13th Amendment — which, as you should remember, was passed by Congress in 1865 to formally end the practice of slavery in the United States, institutionalizing President Abraham Lincoln's 1863 Emancipation Proclamation. Trumpeting the revolutionary nature of the lawsuit, PETA carpet-bombed media with releases declaring their action the "first ever" to apply the 13th Amendment to "nonhuman animals."

Of course, maybe it's never been done before because it's a terrible idea. "It's a sure loser," says attorney and legal scholar Steven Wise. "I've taught for the last 21 years, and every year, some law student comes up with the hackneyed idea of filing suit on behalf of animals using the 13th Amendment; every year, we talk about the pros and cons, and it turns out there are lots of cons and absolutely no pros. It's foolish, and I'm quite astonished that PETA — or anyone — would choose to do it."

It should be noted here that Wise is actually on PETA's side. One of the most prominent legal voices in the animal rights movement, Wise is the author of the seminal books Rattling the Cage: Toward Legal Rights for Animals and Drawing the Line: Science and the Case for Animal Rights, as well as the former president of the Animal Legal Defense Fund. And while he squarely agrees with PETA that imprisoning orcas and forcing them to perform for audiences meets the moral definition of slavery, he believes the constitutional case is one that's currently impossible to make and win.

"There's a hierarchy of rights, and constitutional rights are the most difficult to get for anyone, whether human or nonhuman," he says. "I'd never do that until there'd already been 20 or 30 years of successful litigation. You run right into the doctrine of stare decisis, which makes changing constitutional decisions extraordinarily difficult. Look at Roe v. Wade, which has maintained for decades in the face of dozens of challenges. So jumping straight to the top like that is just ridiculous."

Wise has spent the past two decades taking the opposite tack, building what he calls a "massive foundation" of case precedent and scientific documentation through his nonprofit Center for the Expansion of Fundamental Rights in preparation for a grass-roots-level legal campaign. He's concerned that PETA's flamboyant action might end up compromising his more measured and cautious efforts. "Their hearts are in the right place, but boy oh boy, they're going to lose so fast," he says. "We're just crossing our fingers that the judge ends up ruling on as narrow a ground as possible."

The separate effort that Wise and CEFR have been engaged in is a simple one: They're seeking a to persuade a court that under common law, an animal has personality. This isn't a reference to charm or charisma: Legal personality is defined as having the status of being a "person" under law, and thus, having a set of recognized and enforceable rights, responsibilities, benefits and protections.

"I like to put it this way: I'll hold up a water glass, and say 'The goal is to turn a nonhuman animal into this glass,'" says Wise. "Is this the kind of being that has the capacity to be a legal container for rights? Obviously, our view is that the answer is yes, and we're doing everything we can to set it up so a court, ideally a state supreme court, will agree."

You'll note that in the vocabulary used by Wise and other animal rights advocates, one curious term sticks out: "nonhuman animal." (In fact, using the word animal without the prefix "nonhuman" is grounds for a firm but polite interruption and correction.)

That's because a central pillar of the current ethical and legal arguments for granting (nonhuman) animals personhood is the assertion that humans are also animals. The amount of genetic difference between human beings and, say, chimpanzees is just 1 person; for that matter, we share as many as 60 percent of our genes with fruit flies.

It's a smart, jiu-jitsu rebalancing of the debate. Pleas to anthromorphic empathy — essentially, that animals are a furry or scaly or slimy subset of humanity — may be great for fundraising, but they're nonstarters in the arenas of philosophy and law. But if one accepts that humans are merely a subset of the larger animal population, then the argument over rights goes from digital to analog: The debate is not whether animals should have rights, it's where along the spectrum of "animalness" the ability to have certain rights should begin. And that's a debate that Wise and like-minded activists are ready to have.

"Once you establish that humans are just a kind of animal, then you can make the case that withholding rights from other animals springs from one of two things: Physicalism or ableism," says ethicist David Sztybel, a research fellow at the University of Vienna who writes and lectures widely on the philosophical grounding of animal rights. "You're arbitrarily discriminating against certain animals because they're physically different, or because they're less gifted than human animals. And that's something we reject entirely in the human case, but when we're dealing with the nonhuman world, that logic goes right out the window."

But both Wise and Sztybel agree that an incrementalist approach to winning rights for nonhuman animals is necessary — obtaining them over time and gradually expanding them to include a broader span of species as society adapts to the new reality of nonhuman-animals-as-people. That's how the landscape of rights has evolved within human animal society, after all.

All of which makes PETA's showboating here all the more problematic. The intended consequences of the lawsuit are plain: Winning release for five orcas, and establishing that holding animals captive for the purposes of entertainment is a violation of their natural rights. But in the highly unlikely circumstance that PETA wins its case and any appeals, and manages to hypnotize the Supremes — "hey, if corporations can be people..." — the unintended consequences would be almost unimaginably broad-reaching.

"The implications would be quite substantial," notes Harvard law professor Mark Tushnet, one of the nation's foremost constitutional scholars, and an expert in the legal history of U.S. slavery. "The conditions under which many animals are kept can easily be described as involuntary servitude or worse. Livestock comes to mind. Think of veal calves, which are raised in extremely confined circumstances for use as food. Dairy cows. Would you begin distinguishing between free-range and coop-raised chickens? What about companion animals? How do you determine the willingness of a pet to be a part of your household?"

The notion of whether a nonhuman animal has the ability to make uncoerced choices raises other, more extreme issues: "You might have people defending against charges of bestiality on the grounds that the sheep consented," he jokes. "Of course, then you'd have to deal with age of consent — do you use sheep years or human years?" Not as humorous a consideration as it might seem, given the recent buzz about Malcolm Brenner's book Wet Goddess — his memoir of a real-life nine-month-long "affair" with a female theme park dolphin in the 1970s.

And that's just the tip of the iceberg. In 1883, in United States v. Stanley, one of the first major tests of the 13th Amendment, the Supreme Court determined that its impact went beyond simply the nullification of slavery, stating that the Amendment also impacted the "badges and incidents" of slavery — and that subsequent legislation had secured "to all citizens of every race and color, and without regard to previous servitude, those fundamental rights which are the essence of civil freedom, namely the same right to make and enforce contracts, to sue, be parties, give evidence, and to inherit, purchase, lease, sell and convey property, as is enjoyed by white citizens." (White human-animal citizens, that is.)

Given the above, the next battle over animal rights might be a fight over whether animals can be natural-born Americans. And if so — shades of Incitatus http://orsp.in/u7RCDe, the favorite horse that Emperor Caligula named to the Roman Senate — is it just a matter of time before a real donkey or elephant ends up running for the White House?

Jeff Yang, Pop & Politics blogger for "It's a Free Country," writes the column Tao Jones for the Wall Street Journal Online. Follow him on Twitter at @originalspin.