Although the "leave" campaign often focused on emotional arguments about immigration, there are in fact many reasons those in favor of leaving believed it would benefit the UK. They came from across the political spectrum, and some of the arguments even contradict others. Here are seven of the most significant.
Argument 1: The EU threatens British sovereignty
This is probably the most common argument among intellectual-minded people on the British right, expressed by Conservative politicians such as former London Mayor Boris Johnson and Justice Minister Michael Gove.
Over the past few decades, a series of EU treaties have shifted a growing amount of power from individual member states to the central EU bureaucracy in Brussels. On subjects where the EU has been granted authority — like competition policy, agriculture, and copyright and patent law — EU rules override national laws.
Euroskeptics emphasize that the EU’s executive branch, called the European Commission, isn’t directly accountable to voters in Britain or anyone else. British leaders have some influence on the selection of the European Commission’s members every five years. But once the body has been chosen, none of its members are accountable to the British government or to Britons’ elected representatives in the European Parliament.
Argument 2: The EU is strangling the UK in burdensome regulations
Critics like Johnson say the EU’s regulations have become increasingly onerous:
Sometimes these EU rules sound simply ludicrous, like the rule that you can’t recycle a teabag, or that children under eight cannot blow up balloons, or the limits on the power of vacuum cleaners. Sometimes they can be truly infuriating – like the time I discovered, in 2013, that there was nothing we could do to bring in better-designed cab windows for trucks, to stop cyclists being crushed. It had to be done at a European level, and the French were opposed.
Many British conservatives look at the European bureaucracy in Brussels the same way American conservatives view the Washington bureaucracy. Gove has argued that EU regulations cost the British economy "£600 million every week" ($880 million). (Though this figure is disputed.)
Argument 3: The EU entrenches corporate interests and prevents radical reforms
This is the mirror image of the previous two arguments. Whereas many British conservatives see the EU as imposing left-wing, big-government policies on Britain, some on the British left see things the other way around: that the EU’s antidemocratic structure gives too much power to corporate elites and prevents the British left from making significant gains.
"The EU is anti-democratic and beyond reform," said Enrico Tortolano, campaign director for Trade Unionists against the EU, in an interview with Quartz. The EU "provides the most hospitable ecosystem in the developed world for rentier monopoly corporations, tax-dodging elites and organized crime," writes British journalist Paul Mason.
This left-wing critique of the EU is part of a broader critique of elite institutions more generally, including the World Trade Organization, the International Monetary Fund, and the World Bank. Brexit supporters on the left would have a lot in common with Americans who are against trade deals like the Trans-Pacific Partnership.
Argument 4: The EU was a good idea, but the euro is a disaster
The United Kingdom has had a significant faction of euroskeptics ever since it joined the EU in 1973. But until recently, this was a minority position.
"There are nearly 130 Conservative MPs who have declared for leaving the EU," economist Andrew Lilico told me last week. "If you went back 10 years, you would have struggled to find more than 20 who even in private would have supported leaving the EU."
So what changed their minds? The global recession that began in 2008 was bad around the world, but it was much worse in countries that had adopted Europe’s common currency, the euro. The unemployment rate shot up above 20 percent in countries like Greece and Spain, triggering a massive debt crisis. Seven years after the recession began, Spain and Greece are still suffering from unemployment rates above 20 percent, and many economists believe the euro was the primary culprit.
Luckily, the UK chose not to join the common currency, so there’s little danger of the euro directly cratering the British economy. But the euro’s dismal performance still provides extra ammunition to Brexit supporters.
Many economists believe that deeper fiscal and political integration will be needed for the eurozone to work properly. Europe needs a common welfare and tax system so that countries facing particularly severe downturns — like Greece and Spain — can get extra help from the center.
But that makes Britain’s continued inclusion in the EU awkward. Britain is unlikely to go along with deeper fiscal integration, but it would also be unwieldy to create a set of new, parallel eurozone-specific institutions that excluded the UK.
So, the argument goes, it might be better for everyone if the UK got out of the EU, clearing the path for the rest of the EU to evolve more quickly into a unified European state.
Argument 5: The EU allows too many immigrants
The intellectual case for Brexit is mostly focused on economics, but the emotional case for Brexit is heavily influenced by immigration. EU law guarantees that citizens of one EU country have the right to travel, live, and take jobs in other EU countries.
British people have increasingly felt the impact of this rule since the 2008 financial crisis. The eurozone has struggled economically, and workers from eurozone countries such as Ireland, Italy, and Lithuania (as well as EU countries like Poland and Romania that have not yet joined the common currency) have flocked to the UK in search of work.
"In recent years, hundreds of thousands of Eastern Europeans have come to Britain to do a job," British journalist and Brexit supporter Douglas Murray told me last week. This, he argues, has "undercut the native working population."
The UK absorbed 333,000 new people, on net, in 2015. That’s a significant number for a country Britain’s size, though according to the CIA the UK still received slightly fewer net migrants, relative to population, than the United States in 2015.
Immigration has become a highly politicized issue in Britain, as it has in the United States and many other places over the past few years. Anti-immigration campaigners like Nigel Farage, the leader of the far-right UK Independence Party, have argued that the flood of immigrants from Southern and Eastern Europe has depressed the wages of native-born British workers. Some voters are also concerned about immigrants using scarce public services.
"One of the causes for the great public disgruntlement," Murray argues, is that Labour governments at the turn of the century "massively understated the numbers [of immigrants] to be expected," creating public distrust of current pledges to keep migration under control.
Argument 6: The UK could have a more rational immigration system outside the EU
While many Brexit supporters simply want to reduce the amount of immigration overall, others argue that the UK could have a more sensible immigration system if it didn’t have the straitjacket of the EU.
EU rules require the UK to admit all EU citizens who wants to move to Britain, whether or not they have good job prospects or English skills.
"Leave" advocates argue that the UK should be focused on admitting immigrants who will bring valuable skills to the country and integrate well into British culture. They mention the point-based immigration systems of Canada and Australia, which award potential migrants points based on factors like their language and job skills, education, and age. That, "leave" advocates argue, would allow the UK to admit more doctors and engineers who speak fluent English, and fewer unskilled laborers with limited English skills.
Argument 7: The UK could keep the money it currently sends to the EU
The EU doesn’t have the power to directly collect taxes, but it requires member states to make an annual contribution to the central EU budget. Currently, the UK’s contribution is worth about £13 billion ($19 billion) per year, which is about $300 per person in the UK. ("Leave" supporters have been citing a larger figure, but that figure ignores a rebate that’s automatically subtracted from the UK’s contribution.)
While much of this money is spent on services in the UK, Brexit supporters still argue that it would be better for the UK to simply keep the money and have Parliament decide how to spend it.