A grand conspiracy is afoot, and it starts right here in Missouri.

So says none other than Joe “The Plumber” Wurzelbacher, John McCain’s improbable sidekick in the 2008 presidential campaign. Liking the limelight and desperately searching for a new gig, Joe has lighted upon the Missouri ballot proposition cracking down on puppy breeding abuses.

Joe wants you to know that Proposition B is not really about making sure that dogs have access to healthy food, clean water, reasonable veterinary care, protection from extreme cold and heat, and room to move around.

No. Prop B is a plot by the dreaded Humane Society of the United States, “simply to get rid of ALL dog breeding in Missouri — the unlicensed AND licensed breeders.”

But it doesn’t stop there. Here’s Joe, on the website Alliance for Truth, dedicated to “exposing hidden political agendas.”

“This bill is just a stepping stone. HSUS eventually wants to extend this law to ALL animals. Their idea of utopia is a United States with NO animal ownership; NO meat to eat; NO pets; NO hunting; NO fishing; NO service animals.”

Is that the end of it? Oh, indeed not. More from Joe:

“Even the extinction of our food industry isn’t the scariest part of this whacko liberal agenda. A law is only as good as it’s enforced. And HSUS is happy to fill the void. HSUS has now become the self-appointed law enforcement of the animal world. We have to draw the line and hold these radical animal rights activists back.”

Wurzelbacher’s rantings could be dismissed as comedy but for one thing: His arguments have been voiced many times in the halls and chambers of the Missouri Capitol.

That’s why the Humane Society mobilized to get Proposition B on the ballot. Animal protection measures are radioactive in the state legislature.

Elected officials in Missouri have argued that tougher rules for puppy breeders are the first step to limits on livestock production. They portray the Humane Society (HSUS to opponents) as a fringe organization determined to turn us into a nation of vegans.

Meanwhile, Missouri holds the dubious status of the “puppy mill capital” of the U.S., with about 1,500 licensed breeders supplying four of every 10 puppies sold at pet stores around the nation — many with breeding and health problems. Officials believe hundreds of unlicensed breeders also operate in the state.

Law enforcement raids continually turn up starved, sick and mangy animals, some stacked atop one another in wire cages.

Contrary to what Wurzelbacher and others claim, existing laws don’t adequately protect dogs. Missouri’s animal care facilities act is 18 years old and lax compared with animal welfare laws in other states.

“The provisions ensure that the dogs survive. It does not ensure that they’re treated humanely,” said Barbara Schmitz, director of the Humane Society of Missouri.

As Schmitz observed, opponents of Proposition B don’t want to talk about the way dogs are treated. So they hide behind smoke screens and outright falsehoods.

Experience from other states debunks the claim that the new regulations would “put almost every breeder in Missouri out of business,” as Wurzelbacher warns breathlessly. In any case, the demise of a business that forces animals to exist in misery is no great loss.

And although some states empower employees of animal protection groups to inspect breeding operations and enforce laws, in Missouri those responsibilities would fall to Department of Agriculture employees and local police and sheriff’s departments.

Wurzelbacher’s ominous vision of “HSUS employees running around with guns and police-like badges breaking down doors,” would not play out here.

Joe the Plumber would love to throw a wrench into the animal welfare campaign. But his conspiracy theory leaks like a bad faucet.