It is now clear that the possibility of meaningful immigration legislation — reform that would provide millions with a path to legalization and relief — is dissipating fast. The Senate parliamentarian, Elizabeth MacDonough, delivered a heavy blow when she blocked Democrats from attaching a series of measures to the budget through reconciliation. Frustrated activists reacted by asking Vice President Harris and Senate Democrats to ignore MacDonough’s opinion, but that seems very unlikely. Barring an unexpected turn of events, consequential immigration reform will be left, again, as an unfulfilled promise.

The bad news for the immigrant community doesn’t stop there. After Donald Trump’s defeat in 2020, there was reasonable hope that the Republican Party might take a step back from Trump’s nativist, anti-immigrant rhetoric. Those hopes have been dashed. The former president has picked up where he left off, as have some of his acolytes in the media. It seems inevitable that anti-immigrant demagoguery will be one of the defining themes of next year’s midterms and the 2024 presidential election.

If so, advocates will have to turn their attention, once more, to how best to convey the importance of immigration in the United States. Many voices focus, rightly, on the moral argument for reform. Millions of undocumented immigrants have built lives that are wholly rooted in America and American values. In an ideal world, this argument should suffice. But since polarization and gridlock now define our political context, perhaps there’s a more pragmatic point to make.

A couple of years ago I interviewed Dermot Hayes, a professor at Iowa State University, for a piece on the importance of immigrant labor. Hayes told me that Iowa’s pork industry would collapse without immigrants. “At the labor level — the people who actually perform the work — I would guess at least 80 percent of them are immigrants,” he said. Immigration experts have long argued that the hypothetical absence of the country’s immigrant workforce would lead to enormous economic distress and the collapse of a number of industries crucial to America’s economy.

Few people have had to grapple with what would happen if immigrant labor did in fact disappear from the United States.

Now, thanks to the United Kingdom, we have a clear picture of what the scenario would really mean.

Britain’s pork industry is in crisis. A shortage of butchers has led to a bottleneck of up to 120,000 pigs that, under normal circumstances, would be destined for human consumption. According to a report in the Guardian, “Animals ready for slaughter but stuck on farms require feeding and housing, causing financial difficulties for farmers. Meanwhile, large pigs which are overdue for slaughter often grow by about 1 kg [2.2 pounds] a day, becoming too large for slaughterhouses to handle.” Desperate British producers have begun slaughtering hundreds of mature pigs and even piglets to ease the overload. It’s a heartbreaking crisis.

“I have had grown men in tears on the phone just at the thought to having to contemplate killing healthy animals,” Zoe Davies, a pig industry spokesperson, told the Guardian.

The crisis offers relevant lessons for the United States, the most important of which is the consequences of anti-immigrant policies. The current predicament of the British pig industry is a direct consequence of Brexit. Changes in immigration policy that followed Britain’s exit from the European Union forced tens of thousands of essential workers in different industries to leave Britain. The exodus has led, for example, to severe shortages of around 100,000 specialized freight truck drivers and, of course, the butchers who kept the British pig industry going. “Workers have left processing plants and gone home because a lot of them are eastern European,” Davies told BBC Radio 4.

The issue illustrates, in addition to the stubbornness of Brexit backers, the concrete risks that a society faces if it gives in to nativist prejudice. If the United States really did expel part of the immigrant community in a short time, the collapse of various industries would be even more serious than the current British crisis. The number of U.S. industries that depend on immigrant labor — not just the meat industry but also other farming, construction and more — is considerable.

Nativism may function as sinister rhetoric, but in practice it is an infallible recipe for very concrete collapse. Pro-immigrant activists should explain this in no uncertain terms next time the “build a wall” chant breaks out.