"Proposition B" ballot initiative passed by a small margin on Election Day, created what may be the mother of all unintended consequences. As things stand, a flood of unwanted dogs could be pouring into Missouri pet shelters in the coming months.

Most of Proposition B is redundant, calling for standards that have existed statewide since 1992. But it did create a few new requirements for licensed dog-breeding businesses. (The truly bad "puppy mills" will keep on operating under the law's radar, just like brothels and meth labs.)

The biggest change that Proposition B will bring is a cap on the number of dogs a breeder can own. Henceforth, 50 is the limit. Even if a breeder has two dozen employees giving 51 dogs daily massages, pedicures and catered meals, that won't be good enough.

Many breeders will simply close their doors. And many more will find themselves with more dogs than the law allows. All of them will send a canine tidal wave to pet shelters. Unless Missourians suddenly get the urge to build dozens of new pet-adoption facilities, most of those animals won't leave the shelters alive.

The resources of pet shelters everywhere are stretched paper-thin. And when shelters run out of room, it's common to "put down" animals with comparatively little chance of being adopted.

The implementation of Proposition B could make this already harsh reality far more grim.

A looming flood of unwanted dogs and puppies presents the perfect opportunity for national animal protection groups to step up to the plate. But the Humane Society of the United States, the organization best equipped to fund Missouri's pet shelters, is the same one behind Proposition B. And it's not helping.

HSUS is a Washington, D.C., lobby group that isn't affiliated with Missouri "humane societies." In contrast with its PR campaigns, it doesn't run a single pet shelter anywhere.

Last year HSUS took in $100 million but made only six grants to Missouri pet shelters, totaling less than $43,000, according to its filings with the IRS.

Proposition B, on the other hand, cost HSUS at least $2.18 million. But with another $160 million in assets, the group doesn't seem interested in funding a fix for the aftermath.

Of course, there's an outside chance the coming pup-pocalypse won't materialize. Since Prop B is not a constitutional amendment, state legislators can still amend it. Regardless, we should all contribute what we can to Missouri pet shelters and rescue groups that will be left holding the bag.

HSUS, by far the wealthiest animal rights group on the planet, should open up its wallet instead of leaving Missourians to scoop up what it created. At the very least, HSUS should commit to spending as much in post-election grants to Missouri shelters as it did passing Proposition B.

It's high time the fat cats did something more meaningful for dogs than collecting signatures on clipboards and popping champagne corks. For the sake of its own image, HSUS needs to start showing that its name means something.