On June 23, Britain faces a fateful decision: whether or not to leave the European Union. And the world will be watching. (Daron Taylor,Jason Aldag,Danielle Kunitz/The Washington Post)

On Thursday, the British public will vote on whether their country should leave the European Union.

This move to exit the E.U. has dominated political discourse in the country over recent months. It even has its own headline-friendly portmanteau: Brexit.

Understandably, to some outsiders, it may well seem like small fry compared with some of the other scary problems facing the world right now. However, a potential British exit from the E.U. would have enormous consequences for Europe and, by extension, the world. And while the debate about British identity and the E.U. began politely, it has since taken on a far darker tone — last week, a politician was killed in an act of violence that many linked to the vote.

So, for all of you confused non-Europeans out there wondering what exactly the Brexit vote is really about...

Wait ... could Britain could really leave the E.U.?

Yes, it really could.

The nationwide vote on Britain's E.U. membership is a referendum on the issue. While the referendum's outcome isn't itself legally binding, Prime Minister David Cameron has promised that he will trigger Article 50 — the mechanism that allows countries to leave the E.U. — if a majority of voters back Brexit.

Cameron had promised a referendum during the 2015 general election campaign, largely as a means of securing his support from Euro-skeptics. The date was set earlier this year.

How will the vote work?

The vote will be open to all British, Irish and Commonwealth citizens who reside in Britain or Gibraltar and have registered to vote. British citizens living abroad will be able to vote as long as they have registered to vote in Britain during the past 15 years.

Voters will make their way to a polling station on Thursday, where they will be asked one simple question: "Should the United Kingdom remain a member of the European Union or leave the European Union?" They will then be asked to check a box that reads "remain" or another box that reads "leave."

The ballot will look something like this:


Polls will open at 7 a.m. and close at 10 p.m. local time on Thursday. Britons will probably find out the result early the next morning.

Why do so many Brits want to leave the E.U.?

That's another tricky question.

Britain has long had an awkward relationship with the E.U. The country stalled on joining the European Economic Community (EEC), the precursor to the union, until 1973. Controversy over the terms of its membership led the country to hold a referendum in 1975, which the pro-Europe side won. Britain has avoided becoming too intertwined with some of Europe's institutions, however: It has not switched to the euro, and it is not a part of the Schengen Agreement, which did away with border controls between the countries.

Although it's far from perfect, most analysts argue that union membership has been a boon for Britain, which suggests that, perhaps, the argument to leave may be based more on emotion than economics. It might be because of the sea that separates Britain from continental Europe, the memories of the British Empire, or the special relationship with the United States, but many in Britain have never really considered themselves a part of Europe. Many Britons hate the idea of giving up sovereignty to a bunch of gray Eurocrats.

Most polls suggest that immigration may be the central issue in the Brexit debate. Many Britons feel that E.U. migrants who legally move to Britain are taking jobs from local people and abusing the country's benefits system. The E.U.'s troubling response to a recent wave of migrants and refugees from the Middle East and Africa has only made things worse.

Who is pushing for a vote to "remain" in the E.U.?


Prime Minister David Cameron and Mayor Sadiq Khan greet supporters during the launch of the battle bus for the "remain" campaign in London on May 30. (Facundo Arrizabalaga/European Pressphoto Agency)

Most high-level politicians, including Cameron, Labour leader Jeremy Corbyn, and the leadership of the Liberal Democrats and the Scottish National Party, are supporting the vote to remain in the E.U.

Additionally, a number of celebrities have backed the "remain" vote — including J.K. Rowling, Benedict Cumberbatch, David Beckham and Elton John.

Who is pushing for a "leave" vote?


The leader of the U.K. Independence Party, Nigel Farage, talks to supporters in Birmingham on May 31, while campaigning for Britain to leave the European Union. (Christopher Furlong/Getty Images)

Over the past few years, the U.K. Independence Party (UKIP) and its idiosyncratic leader, Nigel Farage, have found a modicum of success with an anti-E.U. message. While its message was initially somewhat one the fringe, it has found increasing support from Britain's mainstream Conservative and Labour parties.

Perhaps most notably, top members of the Conservative government have broken with Cameron on his Brexit policy. Boris Johnson, the colorful former London mayor, is probably the highest-profile politician to throw his weight behind the "leave" campaign.

Some celebrities have come out as supporting the "leave" vote, though not as many as those in the "remain" camp: Perhaps the most notable is actor Michael Caine, who has said that Britain should not be "dictated to by thousands of faceless civil servants."

What does the rest of the world think?

Generally, most foreign leaders have sided with the "remain" crowd. Many European leaders seem concerned about the precedent that a Brexit vote might set in the E.U. Other foreign leaders, such as President Obama, have argued that a Brexit would diminish Britain on the world stage and perhaps set off broader chaos.

Obama's intervention in the Brexit debate drew serious anger from some anti-E.U.-types, with Farage declaring him the "most anti-British American president there has ever been" and Johnson suggesting that Obama's Kenyan heritage made him predisposed to want to see Britain fail.

That's not to say that there's no support for a Brexit from international figures. Perhaps more notably, U.S. presidential hopeful Donald Trump has offered pro-Brexit views in interviews, though he has clarified that he was not making recommendations and was just talking personally. Russian President Vladimir Putin hasn't come out in favor of Brexit, but he has said that he was confused by Cameron's decision to hold the vote.

"If it's such a problem, why did he initiate this, if he is against it himself?" Putin said at a meeting on the sidelines of the St. Petersburg International Economic Forum last week.

This all sounds a little heated. I heard something about a battle of flotillas on the Thames...

Yes, amazingly, that's true. Somehow, the Brexit debate devolved into two rival groups of flotillas facing off on the Thames River last week.

A week before Britons vote in a referendum on continued EU membership, campaigners from the 'leave' and 'remain' camps take to the River Thames on rival boats near parliament. (Reuters)

You can read the full run-down of how that happened here, but essentially it's this: Farage led about 30 fishing boats down the Thames to Britain's Parliament in a bid to show how the country's fishing community had been hurt by E.U. laws. On the way, he was ambushed by Irish rock star Bob Geldof, who had his own flotilla of E.U. supporters. The two sets of boats faced off on the Thames, spraying each other with water and attempting to use their sound systems to drown the other one out.

It was, to be frank, one of the most ridiculous moments in politics anywhere on the globe. But it was followed by something far darker.

What happened to Jo Cox and how does it relate to Brexit?


Flowers and other tributes to Jo Cox, a 41-year-old British lawmaker killed June 16, lie outside Parliament in London on June 17. The man accused of killing her is said to have shouted "Britain first" when attacking Cox. (Matt Dunham/AP)

The day after the Brexit flotilla, Jo Cox, a recently elected member of Parliament, was stabbed and shot while in her constituency in the town of Birstall. Cox, a mother of two, later died from her injuries.

The killing prompted a reckoning for both camps of the Brexit debate. Cox was pro-"remain," but she was also a powerful voice for refugees. The man accused of killing her, Tommy Mair, is said to have shouted "Britain first" when attacking her and has been linked to far-right groups.

When asked to give his name in court after the attacks, Mair said, "My name is death to traitors, freedom for Britain."

While Mair is miles from being representative of the vast majority of pro-Brexit campaigners, Cox's killing sparked widespread discussion of the tone of the debate ahead of the referendum. Both "leave" and "remain" campaigns were suspended for two days as a mark of respect for Cox.

What would happen if Britain left the E.U.?

It's hard to say.

No country as large as Britain has voted to leave the union before (Greenland, a self-governing territory of Denmark, voted to leave the EEC, the E.U.'s predecessor, in 1982 but in very different circumstances). That, in itself, may be the biggest problem. If Britain left the E.U., it would be a sign to other anti-E.U. groups across Europe that countries can actually exit the union if they want to. That could have a big impact on the continent, where anti-E.U. parties such as France's National Front have won significant electoral support in recent years.

By proving that membership in the union is reversible, a Brexit could severely damage the very foundations of the E.U., a project that is a hugely important attempt to create unity on the continent after the ravages of World War II. As The Washington Post's Michael Birnbaum reports, one recent Ipsos Mori poll found that 55 percent of French voters and 58 percent of Italian voters wanted plebiscites of their own.

For Britain, the economic effects of leaving are a subject of fierce debate. Some Euro-skeptics argue that the union will want to maintain good economic relations with Britain, effectively allowing the country to have its cake and eat it. But it's also possible that E.U. officials would impose tough trade restrictions on Britain as a warning to others that might want to leave.

Additionally, London's status as Europe's financial capital would look shaky if Britain left (HSBC is warning that it may move a thousand finance jobs from London to France if Britain quits the union), and a Brexit may well re-spark the campaign for an independent Scotland, because of the pro-E.U. sentiment held by a large number of Scots.

What would happen to Cameron?

If Britain votes to leave the E.U., Cameron is widely expected to resign. Many view his decision in the 2015 election to promise a referendum — an election he comfortably won — as a disastrous one, sowing the seeds of his own eventual demise and creating a rift within the country.

On the other hand, if the "remain" camp emerges victorious in the referendum, he is probably safe, though he has already suggested that he will not seek a third term as prime minister.

How long would it take for Britain to leave the E.U.?

The minimum period spelled out in Article 50 is two years, though it is possible that the negotiations could take far longer — some even say 10 years. Anand Menon, professor of European politics at King’s College London, told the Guardian this year that the leadership battle to replace Cameron would probably add to the delay. “I imagine that there would be Tory leadership contest, and the platform would be, ‘Here’s what we do next,' ” he said.

There's also a slim possibility that members of Parliament could try to block the exit from the E.U., though it would be an extremely bold move to defy voters so blatantly.

What are the polls saying about what will happen?

It has been a roller-coaster. While initially polls showed a strong lead for the "remain" vote, as the day of the referendum got nearer and nearer, polls slowly began to show a slim majority for the "leave" campaign. Now, in the last week of voting and in the aftermath of Cox's killing, things seem to have swung back toward the "remain" camp.

But polling companies have been wildly wrong in a number of recent British elections, including the general election of 2015 and the Scottish referendum on independence the year before. If recent history teaches us anything, it is that we won't really know what to make of the Brexit vote until Friday.

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