There’s no way we’re getting in your trailer. (JIM URQUHART/Reuters)

Over the past few weeks, Republicans have struggled to put together a highway-spending bill that can pass through the House. The original five-year proposal wasn’t acceptable to the party’s rank-and-file — partly because it was too expensive for fiscal conservatives, and partly because of disputes over transit funding and drilling. A newer, slimmed-down version hasn’t passed muster, either. So we’re still waiting to see what they come up with. But this tidbit about horse carriages from Politico’s rundown was eye-catching:

Concerns run the gamut. GOP leadership likes to say this bill doesn’t have earmarks, but the concerns are still overwhelmingly parochial. For example, pockets of lawmakers disagree with the ban on double-decker horse carriages — it hurts the West and rodeos, they say.

Wait, the ban on what now? Here’s some backstory: Over the past decade, Congress has gradually taken a series of moves to defund and restrict horse slaughtering. (States have been acting too: In 2007, Illinois and Texas moved to shut down the last remaining horse-slaughtering plants in the United States.) A subsequent report from the Government Accountability Office found that this didn’t really end the practice of horse slaughter — horses were still getting shipped across the borders to Canada and Mexico. Still, policies have been steadily moving against the practice.

And, to that end, the Department of Agriculture had proposed a rule banning the transport of horses on double-decker trailers en route to slaughter, as this was a fairly unsafe and inhumane way to ship them. The trailers, after all, were typically designed for smaller animals like pigs and proved far too cramped for horses, who would frequently slip and fall and risk serious injury. What’s more, the trucks were prone to tipping over on highways, leaving a rather macabre tableau of horse carcasses strewn among the wreckage. (One notorious and grisly incident occurred in 2007, when a double-decker trailer carrying 59 Belgian draft horses wiped out near Wadsworth, Ill.)

Then, last year, a bipartisan gaggle of lawmakers in Congress decided to go further and get behind a bill to ban double-deckers for any interstate transport of horses. (See? There are still matters that Republicans and Democrats can agree on.) Only trouble was, various legislators out West — including Montana Sen. Max Baucus, who plays a key role in financing the Senate highway bill — are strongly opposed to the ban. Baucus says the legislation would hurt rodeo operators, who need efficient ways to transport horses. This may seem like a minor issue, but it’s the sort of thing that can bog down the debate over a key reauthorization bills to fund our nation’s roads and highways...

Correction: This post originally said that the GAO had proposed the ban on double deckers — it was merely urging the Department of Agriculture to finalize rules that were already proposed. Thanks to commenter seti_the_first for pointing it out.