You can lead pigs to slaughterhouses, but what happens if they're unable to walk to their deaths?

In California, those "nonambulatory" pigs, as they are called in legalese, are immediately euthanized and prevented from entering the food supply.

But Minneapolis attorney Steven Wells, representing the National Meat Association, recently argued before the U.S. Supreme Court that California's law shouldn't be allowed to trump federal rules regarding slaughterhouses.

Several justices appeared to agree with Wells; Justice Antonin Scalia even declared that "California should just butt out." Even so, we hope the justices will uphold the 3-0 decision made by the Ninth Circuit Court of Appeals, which called the meat producers' argument "hogwash."

This is a case worth watching, because the Supreme Court's ruling could have ramifications for slaughterhouses, meat producers and animal-rights advocates around the country. Although the case before the Supreme Court involves pigs, the 2008 California law extends to downed goats, sheep and cattle at slaughterhouses.

The law was prompted by outcry after a video surfaced showing the mistreatment of downed cows at a slaughterhouse in California's San Bernardino County. The controversy not only led to the largest-ever recall of meat in U.S. history but, in 2009, President Obama ordered that downed cows not be sent to slaughter.

The impact of the video had a chilling effect on the meat industry. In Minnesota, state Rep. Rod Hamilton, R-Mountain Lake, called on the state Legislature this year to make it illegal to produce or distribute videos showing animal mistreatment. This was an obvious effort to silence animal-welfare advocates.

Federal law doesn't require that downed pigs be promptly euthanized. Instead, federal meat inspectors determine whether such animals are fit to be slaughtered and enter the food supply. Sometimes downed pigs are simply fatigued or overheated from travel and recover after a bit of rest. In part, the California law is intended to prevent the mistreatment of downed animals -- such as the procedures shown in the video -- that have occurred at slaughterhouses in an attempt to prod along or revive them. Either way, the animals die, but the California law helps prevent slaughterhouse abuse like that seen on the video.

Under the California law, downed pigs must be promptly euthanized with no chance of entering the food supply, even if they aren't diseased. It's understandable, at least economically, why the Meat Association would object. The group estimates that 3 percent of pigs are downed when they arrive for slaughter, which means pork producers and slaughterhouse owners would take a financial hit.

Wells says it's important that those downed pigs be inspected to ensure they haven't spread a contagious disease to healthy animals. "In my view, the California law is bad for animals and bad for people, too," said Wells.

But that argument strains credibility. As Justice Sonia Sotomayor rightfully pointed out, even if the euthanized animal isn't inspected, "All of the other animals in that pen that are ambulatory ... will by the inspector, the veterinarian, be declared disease-free or not."

The California law has never been implemented fully, because the meat producers obtained an injunction. If California prevails -- and it's our hope that it will -- then states will have the right to impose stricter rules to protect public health and animal welfare as long as they don't interfere with federal rules.

In siding with California, we aren't endorsing the particulars of that state's law. We're only arguing that it doesn't appear to contradict or impose upon federal slaughterhouse rules. The Ninth Circuit Court of Appeals ruled for the state because the law merely "withdraws from slaughter animals that are unable to walk to their death" -- nothing more, nothing less.

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Readers, should animals that arrived to slaughterhouses be immediately euthanizes or given a change to recover, and the possibilty of entering the food supply? To offer an opinion considered for publication as a letter to the editor, please fill out this form. Follow us on Twitter @StribOpinion and Facebook at facebook.com/StribOpinion.