Trouble looms in the effort to keep Britain as part of the European Union.

British Prime Minister David Cameron needs unanimous approval for a special deal for the United Kingdom.

Three years ago, Cameron — under pressure from an anti-EU party and from some members of his Conservative Party — promised he would call a referendum on Britain’s membership in the EU.

If only voters would please re-elect him and his party first.

They did, and now he has to deliver.

He pledged to renegotiate the terms of Britain’s membership in the EU, then hold a simple referendum: Should Britain stay in the EU or leave it?

Thursday will be crunch day.

So what’s happening Thursday?

At a summit in Brussels, Belgium, leaders of the 28 EU countries will gather for a crucial meeting on whether to negotiate a deal that will persuade British voters to stay in the EU in a referendum likely to be held in June. The leaders, some of whom resent Britain’s demands for special treatment, must approve the deal unanimously — a steep hill for anyone to climb.

A report Wednesday in The Guardian newspaper says four Eastern European countries — Poland, Slovakia, Hungary and the Czech Republic — have rejected Britain’s proposals to limit benefits for migrant workers. The report emerged a day before the Brussels meeting.

The European Parliament must also approve.

The EU sprang from the ashes of World War II as a free-trade zone. Its signal achievement has been to allow free movement of goods and people in the hope that economic integration would prevent a new continental war.

Britain has opted out of both those EU provisions, and it views with skepticism the EU’s effort to branch into new fields, regulating everything from pesticides to human rights, and creating a unified foreign policy, too.

The expectation is that the national leaders will gather in the evening, start with a hearty meal, then debate behind closed doors deep into the wee hours.

What is Cameron trying to achieve?

In essence, Cameron is trying to thread the needle. He wants to be able to say the he negotiated firmly with the bureaucrats — sometimes called “eurocrats” — in Brussels. He wants to opt out of the standard EU commitment that its members must work toward “ever closer union.” He wants Britain exempted from having to give various social benefits to newcomers — even from other EU countries — until they have lived in the country for several years.

In the end, he wants to say he has dealt strongly with the hated EU — and, hey, let’s stay in that fine organization because of course it’s in our interest.

Why do many in the UK want to quit?

Police spray tear gas at migrants trying to access the Channel Tunnel in France.
Police spray tear gas at migrants trying to access the Channel Tunnel in France.

Part of it relates to migration — and the large numbers of people fleeing the civil war in Syria have only increased that fear. There is a feeling that new arrivals sponge off British taxpayers, or take their jobs, perhaps for less pay than a native Briton would demand. And in that way they drive wages down and unemployment up.

There seems a whiff of cultural bias as well among a few opponents of British membership in the EU. While there is no outcry about immigration from the United States or Australia, for example, some members of the main anti-EU party, UKIP — the United Kingdom Independence Party — have made remarks tainted by prejudice.

And there is an element of nationalism. There is reluctance to cede sovereignty to the EU, which is what membership involves in some respects.

Have there been problems before between EU and UK?

Yes, indeed.

Britain has always stood apart from the EU to some extent, displaying a bit of the island mentality.

France's Charles de Gaulle, second from right in 1943, opposed UK entry into the Common Market.
France’s Charles de Gaulle, second from right in 1943, opposed UK entry into the Common Market.

While much of the EU involves passport-free travel between member countries, not so with Britain. And when many EU countries scrapped their national currencies in favor of the euro, Britain said no thanks, we’ll stick with the pound.

The country’s difficult relationship with the EU is nothing new. In the 1960s, French President Charles de Gaulle not only opposed Britain’s entry into what was then called the Common Market, he also opposed any negotiations on the topic.

Britain didn’t join the European Community, as it was then called, until 1973, by which time de Gaulle was dead.

And in the 1970s and ’80s, Prime Minister Margaret Thatcher railed against what she saw as the excessive powers of Brussels. She negotiated a rebate for Britain on its contributions to the EU and opposed having “a European super-state exercising a new dominance from Brussels.”

Is there a chance Britain will leave the EU?

Certainly. National referendums can go either way. The British press is largely hostile to the EU, and sometimes presents a distorted picture of it.

Reading the local papers, one might think, for instance, that the EU has a massive bureaucracy. In fact, the EU employs about 23,500 people to look after its 28-nation area. By contrast, there are about 6 million government employees in the UK alone.

And the historic number of people fleeing conflict and poverty in the Middle East and North Africa — most of them bound for Europe — only increases the chances that Britons, fearful about their jobs and their national identity, will try to pull up the drawbridge and go it alone.

Furthermore, while Cameron expects to campaign for Britain to stay in the EU, the Tories are divided on the issue, with some senior members of his party favoring an EU exit.

Still, analysts say it is generally harder to vote for change than for the status quo. Leaving the EU would be change. And that engenders its own fears.

Leaders in some other countries favor an EU with Britain in it. It makes dealing with Europe easier, gives Europe a stronger voice in the world and allows for coordinated European sanctions to be imposed — for example, against Russia for its annexation of Crimea, or against Iran for its nuclear program.

For his part, President Barack Obama has urged Britain to stay in the EU. The UK as a member of the EU “gives us much greater confidence about the strength of the transatlantic union,” Obama said in July.

As reported by CNN