Pro-Brexit politicians are the dog that caught the car. Now immigration is their problem.

The UK’s vote for Brexit on Thursday was, largely, an expression of anxiety about immigration. Polls showed 79 percent of Brits who thought immigration was a "force for good" voted "Remain," while 80 percent of Brits who thought it was a "force for ill" voted "Leave." The release of migration statistics a few weeks before the election — showing that net migration to the UK had reached 330,000 in 2015 — was regarded as a key factor in Leave’s victory.

"It's very important for Britain to get control of our own borders," British journalist and Brexit supporter Douglas Murray said last week.

Well, now they have it. (Sort of.) Now what?

Christopher Furlong/Getty

Here’s the truth: No one really understands yet what migration to the UK post-EU will look like. There’s a solid possibility that not only will migration to the UK not be reduced, but that it could actually increase.

That’s why the first priority for many pro-Brexit politicians appears to be: Get people to reduce their expectations. "Frankly, if people watching think that they have voted and there is now going to be zero immigration from the EU, they are going to be disappointed," EU MP Daniel Hannan told the BBC on Friday. Boris Johnson (the likely next prime minister) emphasized that the UK wasn’t "pulling up the drawbridge": "We cannot turn our backs on Europe. We are part of Europe."

It’s an odd reaction for politicians to have: We won, but don’t get your hopes up. But it makes sense given the reality they’re facing. What UK voters want is extremely clear, but the future of UK immigration policy isn’t clear at all.

The UK’s new immigration policy will depend on negotiations with the EU

It’s hard to answer any question about what the Brexit vote actually means, for the simple reason that Brits may have voted Leave but Britain hasn't actually left.

The Brexit vote is just a signal for the UK government to tell the EU that it wants to withdraw — setting a two-year clock for the governments to negotiate how that would actually work. The UK won’t officially have left until the negotiations are completed and a majority of the European Council approves the terms, or until the two-year window has closed.

Any changes to immigration to the UK from other EU countries — or vice versa — will depend on how those negotiations go.

Daniel Leal-Olivas/AFP via Getty

But once Britain fully withdraws from the EU and wins back the right to control immigration — assuming all that happens — what will Britain do with it?

There wasn’t an official immigration policy associated with Brexit (which makes sense when you consider the UK government was, until this morning, run by a man who didn’t want to leave the EU at all).

Leave supporters have consistently promised that Brexit will not force citizens of other EU countries currently living in the UK to leave. The immigration proposal issued by four prominent Leave supporters (including Boris Johnson) in June promised that EU-citizen residents "will automatically be granted indefinite leave to remain in the UK and will be treated no less favourably than they are at present."

The current British government isn’t so sure that’s possible. (Theoretically, it’s possible that the EU will refuse to agree to it as a term of withdrawal.) They can’t even promise that EU citizens won’t be deported: "The withdrawal process is unprecedented," one Cabinet member shrugged.

Of course, if it is possible, it will mean that the panic about 2015’s record immigration into Britain will end up creating a situation in which more of those immigrants stay permanently in the UK. As the US saw when it increased border security with Mexico, when it’s harder for people to return, they’re less likely to leave at all.

Scott Heppell/AFP/Getty

The leading post-Brexit proposal isn’t all that restrictive

But the most prominent Leave supporters, including likely next PM Boris Johnson, have proposed an "Australian-style points system." Under this proposal, both EU and non-EU citizens who wanted to immigrate to the UK would be judged by how suitable they are for the job they’d hold, and how good their English is.

Brexit supporters argue this would actually make immigration less complicated for people outside the EU, who currently make up a little more than half of all immigration anyway.

For EU citizens, it would certainly be more restrictive than it is right now — since there are no restrictions right now — but it might not be all that much more restrictive. Forty-one percent of EU citizens immigrating to the UK already have a job lined up when they come; it’s certainly possible that many of them will be deemed "qualified" for such jobs under the new UK policy.

Moving to a "points system" makes sense if Brits are worried about being overrun by low-skilled labor or overly "foreign" immigrants. (Many Republicans in the US, for example, advocate for the US to move toward the Australian and Canadian immigration models rather than prioritizing family-based immigration.) But it doesn’t necessarily make sense if one is looking to reduce immigration overall. When Australia came up with its points system, the purpose was actually to increase immigration into the country.

As much as anxiety about intra-EU migration, of course, Brits were worried about an influx of refugees into the country. The EU is certainly taking in a lot of refugees right now — but Britain, even while staying in the EU, is taking in hardly any.

Philippe Huguen/AFP via Getty

More importantly, Britain, unlike most EU countries, has maintained robust border controls. Most migrants attempting to enter the UK illegally find themselves gathered in a massive tent city near Calais, France called "The Jungle" — and UK border officials can prevent them from leaving France.

The agreement between the UK and France that allows the UK to keep its border controls on the French side of the border isn’t an official EU thing. But just like other EU countries have every reason to push for tougher trade controls with the UK to boost their own economies, France has every reason to tell Britain that once it leaves the EU it has to deal with its own detainees. The upshot: The UK might have to house more unauthorized migrants (albeit in detention) within its borders.

Pro-Brexit politicians can’t control their supporters’ fear

Supporters of Brexit aren’t admitting all this just yet, of course. But it helps explain why they’ve spent so much of their post-victory media tour managing their supporters’ expectations.

It’s not just Hannan’s comment that people are "going to be disappointed" with continued EU immigration. Nigel Farage, whose far-right UKIP party is a big reason there was a Brexit vote to begin with, admitted Friday morning that it was a "mistake" to promise that the UK would invest £350 million a week in the National Health Service instead of paying it in EU fees. Several hours after Farage’s walkback, though, that promise was still the header image on the Leave campaign’s Twitter page:

Vote Leave via Twitter

Farage, Hannan, and company, in the aftermath of their victory, look for all the world like the dog that caught the car. They’ve been chasing it assiduously — but did they actually have an idea what they’d do when they caught it?

The Brexit vote has proven that anti-immigrant anxiety is an incredibly powerful force: powerful enough to, in certain circumstances, ensure an electoral victory. But the thing about running on people’s anxieties is that once you get into office, you have the responsibility to alleviate them.

I’ve often wondered what it would be like if, here in the US, a border hawk Republican like former Arizona Gov. Jan Brewer or Ted Cruz or Donald Trump were actually elected president (or even appointed head of the Department of Homeland Security). Having persuaded their followers that the US/Mexico border was lawless, they’d suddenly have to persuade them it had been made safe. Otherwise, they’d be yet more failed politicians who couldn’t keep their promises and America safe.

The Leave campaign knows this. Its immigration proposal says as much:

"If we implement these principles, for the first time in a generation it will be possible for politicians to keep their promises on migration. If they fail, there will be no hiding behind EU rules and the European Court. The British public will be able to decide what immigration policy they want."

That’s a subtweet of lame-duck Prime Minister David Cameron, who promised in 2012 to bring net migration into the UK down to 100,000 a year. (He didn’t even come close; the UK would have missed that target in 2015 even with zero intra-EU migration.) But it’s also a warning to Johnson and anyone else who wishes to succeed Cameron, and to the rest of the politicians who want to run an independent UK.

In fact, those politicians might want to hope their supporters are merely "disappointed" by post-Brexit immigration policy. They might get downright mad.

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