In Europe, we’ve seen the pattern again and again since 2015:

1. Mass low-skilled immigration spurs a backlash
2. The backlash strengthens nationalist parties, who then get 10, 20, 30 per cent of the seats in the legislature
3. The normal political parties create a cordon sanitaire, some kind of promise not to do business with the baddies
4. Finally, domestic politics turns into a huge mess, more volatile, more fractious, more contentious than beforehand.

For almost a decade now we’ve seen versions of this in Belgium, France, Germany, Sweden, and the Netherlands. The entire process gets kicked off by the first step – the waves of mass low-skilled immigration – and the process usually leads to the last step – a worse version of domestic politics.

There’s been a lot of ink spilled blaming the baddies, the new nationalist parties, for their role in the worsening of European politics. And they definitely include more than the usual share of bad actors with evil motives, even by the standards of electoral politics. But as long as Europe stays democratic, allowing free elections and allowing people of all views to run for office, these nationalist parties are going to run and they are going to win seats.

Rather than add to the complaints about the nationalist parties – a worthy task for another time – instead I want to explain why the cordon sanitaire is bad. And I’m not doing that in order to encourage normal parties to start cutting deals with the far right. Instead, I’m going to argue that the cordon sanitaire is so bad, so destructive of good democratic governance, that European countries should cut back massively on their level of low-skilled immigration: European countries should stop fuelling the engine of democratic decline. That won’t be fun, it won’t make you friends in high places, and it’ll be harder to have cheap Ubers and Deliveroo meals.

But in the long run, and maybe even in the shorter run, it’ll improve your democracy. The reason is simple: democracies run on majority rule, and it’s harder to get past 50% agreement when you’ve already decided you can’t deal with 25% of your parliament.

Politics is the art of compromise, and even in a healthy democracy we’re used to seeing how hard it is to come to enough agreement on the details of legislation to get anything meaningful done. But if you’ve decided that 25% of the legislators are beyond the pale, then that means you need two-thirds agreement among the remaining legislators to find a majority to pass anything!

Consider the effort to get 67% of legislators to agree on anything: that’s even more than you need to end a filibuster in the US Senate – they only need 60%! Countries that sign on to a cordon sanitaire are signing on to the high costs of political negotiations, the higher political frictions, and the pattern of repeated failures of coalition governance that entails.

My late colleagues at George Mason University, Gordon Tullock and Nobel Laureate James Buchanan, emphasised that when you move beyond majority rule to this kind of supermajority rule, you raise the negotiation costs of coming to an agreement. And in practice that means that a lot of good deals won’t get done so the can gets kicked down the road and the status quo reigns. Fixing the roads, reforming the military, deciding on the national retirement age – all get harder when you’ve got to reach 51% using just 70 or 80 per cent of the legislature.

For now, the UK may feel immune from such problems, with Labour enjoying a huge Parliamentary majority and your first-past-the-post system making it hard for fringe parties to win seats. But consider how much political capital has been expended in managing the immigration backlash, even before the recent outbreak of far-right riots. Reform UK has already outperformed and isn’t likely to go away. Some Conservatives are openly discussing if they need to form a coalition with Reform to recover electorally, while others want to maintain a cordon sanitaire at all costs. And Reform, or its successors, will pose even more of a challenge if campaigners for electoral reform gain traction.

Yes, there are plenty of ways for democracies to weaken, and the high costs of a cordon sanitaire are just another one. But it’s one that will show up in dozens, maybe hundreds of small ways. It’s like obesity: you know it’s bad, but you can never be sure that a particular bad outcome – a stroke, a heart attack – only happened because the guy was morbidly obese. Literally could’ve happened to anybody.

So don’t expect me to say that this or that bad law, this or that forever-delayed reform, was all due to the political backlash to low-skilled immigration. That’s not how this works. Instead, look at the big picture, check to see which countries are falling into an unusual pattern of policy sclerosis and political volatility. I suspect a good statistician can find evidence for what I’m saying, but you can see it too, if you just look around.

The political backlash to low-skilled immigration makes democracy worse, but it’s possible to end that backlash. If the normal parties make the hard choice to cut way back on low-skilled immigration – perhaps by shifting heavily toward a programme heavily favouring high-skilled immigration – they’ll stop fuelling the declinist engine. And to end with a cliché that has a real chance of being true, ending the immigration backlash will give Europe a better chance at building a more harmonious, more prosperous future.

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Garett Jones is Associate Professor of Economics and BB&T Professor for the Study of Capitalism at the Mercatus Center, George Mason University. He is the author of 'The Culture Transplant', published by Stanford University Press.

Columns are the author's own opinion and do not necessarily reflect the views of CapX.