Great Britain once ruled the largest empire in history, with colonies and dominions that spanned the globe, political and economic influence that wildly exceeded its modest size. Generations of schoolkids were raised on the mantra: "the empire on which the sun never sets."

World War II marked the beginning of the end, and the not-so-United Kingdom votes Thursday on whether to cut itself loose from the European Union, the latest in a long line of moves that would shrink its international presence.

The vote appears close. But regardless of its outcome, the referendum symbolizes Britain's sweeping turn from an outward-looking, global power to a more insular North Sea island uncertain of its place in the world. "From Great Britain to Little England," as many headline writers have summed it up.

Prime Minister David Cameron, who wants to stay in the E.U., thought the referendum would silence critics, many in his Conservative Party, who regard the E.U. as a shackle on Britain that diminishes its sovereignty. Yet Cameron is now battling for his political life, framing the ballot in stark terms that tap into Britain's past glory:

"At my office, I sit two yards away from the cabinet room where Winston Churchill decided in May 1940 to fight on against Hitler, the best and greatest decision perhaps anyone's ever made in our country, right? He didn't quit on Europe, he didn't quit on European democracy, he didn't quit on European freedom. We want to fight for those things today. And you can't win – you can't fight — if you're not in the room."

Despite the loss of global clout, Britain still boasts a resume few can match: a permanent seat on the United Nations Security Council, a nuclear arsenal and a "special relationship" with the United States.

London is a financial capital where multinational firms and foreign billionaires comfortably invest their money. The U.K. has the second largest economy in Europe, having surpassed France and trailing only Germany.

A History Of Euroskepticism

Yet the U.K. has always been an ambivalent member of the Euro club that emerged after World War II. Britain declined to join the E.U.'s forerunner, the European Economic Community, at its 1957 founding. Britain signed up in 1973 — and promptly held a referendum on leaving two years later. It voted overwhelmingly to stay that time.

As a general rule, U.K. citizens who are younger, better educated and live in the wealthier south are more likely to favor staying in the E.U., often citing economic benefits.

Those who are older, working-class and live in less prosperous regions are more likely to favor leaving. The E.U., based in Brussels, imposes too many regulations and has created conditions that allow in too many immigrants, they say.

Yet those battle lines are far from absolute.

"I've been skeptical of [E.U. membership] for some years and that skepticism has now morphed into outright opposition due to what I regard as the arrogance, the wastefulness, the corruption and the incompetence of the Brussels government," British author Frederick Forsyth told NPR's Morning Edition.

Forsyth dismisses the argument that Britain will suffer economically by opting out of the European Union, predicting a mix of benefits and burdens no matter which path the country chooses.

"None of us have a crystal ball," Forsyth added. "So when they say, 'In 10 years this will happen,' they haven't a clue what they're talking about. They're just plucking figures out of clear blue sky."

Proponents of leaving also point to European states like Norway and Switzerland that have been highly successful without joining the Euro club.

The Risks Of Leaving

But those countries never had Britain's larger global ambitions, the other side argues.

"As a single country we would have minimal influence on world affairs. Does anyone seriously think the prospect of British sanctions would alarm [Russian President] Vladimir Putin, or have persuaded Iran to curtail its nuclear program?" Martin Fletcher, the former foreign editor of the Times of London, wrote in a Facebook post.

"We would be willfully removing ourselves from a single market of 500 million people without the faintest idea whether, or on what terms, we would be allowed to continue trading with 27 E.U. states who would want to punish us. Why on earth would we take such a monumental risk?" he added.

The "Leave" supporters claim that the E.U. has chipped away at Britain's sovereignty, and cutting ties would make Britain stronger and freer to act as it chooses. Their motto is "Take Control."

That attitude has long been a current in U.K. politics and perhaps there's no turning back.

"The outward-looking, fully engaged Britain that 'punched above its weight' has already faded away, and not everybody in London is very sorry about this turn of events," U.S. columnist Anne Applebaum wrote last year.

"Without the outside world, they do just fine. They'll always have London, with one of the world's most lucrative financial sectors; they'll always have England, with some of the world's greenest countryside; and they'll always have the memory of a grander history — and maybe that's enough," she wrote.

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