Will Scotland break away? Scotland votes this month on whether to leave the United Kingdom.

• Author: Smith, Patricia
• Position: INTERNATIONAL

Should Scotland dump the United Kingdom and become an independent nation? That's the question 4 million Scottish voters will answer on September 18. If a majority votes "yes," it could weaken or even spell the beginning of the end of the U.K., one of the most important political unions in history.

Among those casting ballots for the first time will be 150,000 16- and 17-year-olds. Because the outcome of the vote will have such a big impact on their futures, Scotland approved a one-time lowering of the voting age from 18 to 16 for the referendum.

Scotland has been part of the United Kingdom--along with England, Wales, and Northern Ireland--since the early 18th century. But a growing number of Scots believe that Scotland would be better off on its own.

There's been talk of Scottish independence for decades, but only recently have political experts given secession any chance of winning an up-or-down vote.

Support for independence has increased to almost 40 percent in most recent polls, while the "no" vote hovers in the high 40s. About one in six Scots remain undecided.

Sean McLaughlan, a junior at the University of Glasgow, supports an independent Scotland. "I would like Scotland to have its destiny in its own hands," he explains.

But that's not how 16-year-old Charlotte Smith of Dumfries sees it.

"I believe we're financially and economically stronger in the larger union," she told the Reuters news agency.

2,000 Years of Tensions

Tensions between Scotland and England go back 2,000 years. In 122 A.D., the Romans controlled most of present-day England. But Emperor Hadrian gave up on subduing the Scottish tribes to the north; instead he built a 75-mile-long wall to keep the "barbarians" out of Roman Britain. (Much of Hadrian's Wall still stands today.)

By the 11th century, Scotland's tribes had come together to form a kingdom. From the start, England was Scotland's greatest rival, periodically gaining control over its northern neighbor.

In 1707, a bankrupt Scotland agreed to enter a union with England: Scotland gave up independence in return for access to English markets. Even at the time, the union was denounced as a sellout. "We are bought and sold for English gold," wrote the Scottish poet Robert Burns.

Scotland prospered under what eventually became the United Kingdom, but it has always maintained a distinct culture: playing bagpipes, eating haggis (a sausage-like dish made of sheep innards], flying the blue-and-white Scottish flag rather than the Union Jack, and men wearing kilts.

In response to growing Scottish nationalism, the British government devised a plan for an elected Scottish parliament, which met in 1999 for the first time since 1707. The parliament controls things like healthcare and education, while the central government in London determines taxation, foreign policy, and defense. (The setup is, in some ways, analogous to the division between states and the federal government in the United States.)

Then in 2011, the Scottish National Party, which favors independence, won a majority in the Scottish Parliament. Suddenly independence was a hot issue. Within a year, Scottish and British leaders agreed to hold a referendum in 2014, the 700th anniversary of the Battle of Bannockburn (see Key Dates).

The referendum is binding and needs to pass by only a single vote...