Will Scotland break up the U.K. in '07?

Yesterday many Scots woke up with a hangover. ''Hogmanay'' -- the Scottish version of New Year's Eve -- is traditionally celebrated with even more vigor and merriment than Christmas north of the border with England. But will that hangover last a full year?

For 2007 includes two important events in the Scottish calendar that, taken together, have the potential to create an enormous headache. The first is the 300th anniversary of the Act of Union that formed the United Kingdom of Great Britain. Usually, it would be celebrated with pomp and circumstance. The second event is the election in May for the devolved Scottish parliament. On present trends, this may make the Scottish National Party the single largest party in Scotland. And Alex Salmond, the SNP leader, has promised an early referendum on breaking up the union and creating an independent Scotland. Thus, Scotland might both celebrate the 1707 Act of Union and dissolve it in the same year.

What are the trends that make this a real possibility? Most obvious is the growing support within Scotland for independence. Opinion polls show more Scots favor independence than oppose it -- and recent ones have shown outright if narrow majorities (52 percent) for full independence.

This figure has been growing steadily for 40 years. British Prime Minister Tony Blair pushed through devolution, creating a devolved Scottish parliament in a new federal U.K., in the belief that it would damp down Scottish support for full independence.

Unfortunately for Blair, Scottish devolution had a larger impact in England than in Scotland. It created a growing awareness that the Scots felt themselves to be very different from the English and even slightly hostile to them. That in turn directed the attention of the English to certain political facts they had hitherto taken for granted but that now seemed unfair:

1. The fact that Britain's public expenditure includes a $50 billion subsidy for Scotland.
2. The ''West Lothian Question.'' This is the apparent unfairness that Scottish MPs in the U.K. Parliament in Westminster get to vote on all issues affecting England, but English MPs are barred from voting on issues -- for instance, housing and education -- that are the responsibility of the Scottish Parliament.
3. The political fact that Britain has a Labor government because of Scottish votes; Labor is in an almost permanent minority in England.
4. The fact that a very high percentage of Labor Cabinet ministers are Scots, including the likely next prime minister, Gordon Brown. (Tony Blair is a Scot, too, but not very noticeably.)

All these things have been true for a long time. But as long as the English and Scots saw each other as primarily British, such things didn't matter. Once devolution emphasized the differences between the Scots and the English, however, the latter began to resent these transfers.

One result is that opinion polls have shown growing English support for the breakup of the United Kingdom and independence for England.

Britain's main political parties are, of course, strongly opposed to any such move. The Tories are supporters of the union in principle. Labor is opposed to Scottish independence because it would rob them of power in the much more important and populous England (which has a population of over 50 million compared to Scotland's 5 million). And both Blair and Brown are horrified by the prospect of an independent Scotland -- Blair because he would go down in history as the prime minister who presided over the breakup of the U.K., and Brown because he would cease to be prime minister in a very short time, perhaps even before he got the job.

In 2007 we can expect a rash of official scare stories from Blair and Brown, joined on this occasion by their Opposition opponents, about the dire consequences of breaking up the U.K. But the trend toward separatist nationalism in Britain is now a very strong and well-established one. This is a case of an irresistible force meeting an immovable object. The outcome is unknowable.

But the lessons are already clear for the United Kingdom -- and for the United States, since both nations are multinational and multiethnic states. Ultimately, national feeling, patriotism, loyalty and a sense of common allegiance exist in the hearts of men and women.

Multinational and multiethnic societies have to work hard at keeping these ties strong precisely because their populations begin by being diverse. If pride in their common nationality is allowed to decay, different ethnic groups soon will discover and resent their differences.

On the 200th anniversary of the Act of Union, Scottish independence would have struck both Scots and English as absurd. Today it is a choice. What will be the choices facing the United States in 2076?