A few days ago I stumbled across this post, from a blogger at Lawyers, Guns, and Money, positing that Wisconsin Governor Scott Walker is 2016’s version of Rick Perry in 2012: “He checks a lot of boxes, on paper, but at the end of the day he just may not be ready for prime time.” The post, which was published in June, was triggered by Walker’s apparent inability to coherently communicate his beliefs about abortion—and had I read it at the time, I suspect it would have struck me as an intriguing hypothesis, given that Walker has been stumbling haphazardly around national politics all year, losing traction in the early polls, and getting crossways with most of the other Republicans running, including Perry 2.0.

This weekend, however, the hypothesis was badly undermined by the seemingly inadvertent ingenuity of Walker’s border security plan:

Wisconsin Governor Scott Walker said in an interview broadcast Sunday that building a wall along the U.S. border with Canada is something worthy of further study.

“That is a legitimate issue for us to look at,” the Republican presidential candidate said on NBC’s Meet the Press program.

This is prima facie ridiculous. But on contemplation, the inanity of the idea is somehow strangely brilliant. The idea of building a wall along America’s northern border is ludicrous. If the United States is going to invest vast amounts of labor and capital in a sprawling infrastructure project, we might as well go for one of the many available options that would improve transportation mobility, or protect vulnerable regions—or, more modestly, have any salutary impact at all. We should hold off on one that would have ruinous effects on economic exchange with one of our major trading partners, and that would send a somewhat unwelcoming message to a neighboring country, one that millions of Americans are directly connected to via family, culture, heritage, commerce, or civic life, to boot.

At the same time Walker’s vision of a northern border wall is not actually a worse idea than Donald Trump’s dream of a southern border wall, which at least half of his rivals have ardently embraced.

Some readers may actually consider both ideas good. I hope not, but just in case the Trump-Walker ticket succeeds next year, let me offer some friendly advice: If we must build both walls, let’s make sure to tackle la frontière first.