Stead Sellers: How Scottish independence is a threat to America too

There's a bigger issue hanging over the Scottish referendum Thursday than who gets the nuclear arms or the North Sea oil. It's a question of identity - and far more important than who the English really are, or how quaintly kiltish the Scottish may feel once they're ungartered from their southern neighbors.

The issue is about more recent Britons and future Britons - immigrants from all over the world who want to call England, Scotland, Wales or Northern Ireland "home" - and dream of their descendants creating a home there, too.

Taking Britain apart, which is what will happen if the Scots vote Thursday to go it alone, risks dismantling a fragile process revived just a decade ago of building a sense of citizenship and even kinship among the islands' old and new residents. It risks letting more young men and women grow up alienated and looking for inspiration overseas. That's a chilling prospect as young fighters leave for Syria and "Jihadi John" wields his barbaric knife - and it's a big burden to place on a plebiscite of some 5 million Scots (less than 10 percent of the British population).

But one of the benefits of being British (I am) is that it's a collective ideal rather than an ethnic identity. By which I mean, it's more Magna Carta and rule of law than kilts or cups of tea. Being British involves believing in, or at least accepting, certain shared and somewhat lofty-sounding values (like individual freedom and fairness). But you don't even have to pretend to like haggis or Morris dancing. That's why it's so much easier to be Bangladeshi British than, say, Sudanese Scottish or Ethiopian English. (Any Italian- or Iranian American will understand that.) Your adopted identity is about the values that attracted you, not adapting to the quirks of cultural heritage.

Britain's ruling elite only recently realized the importance of building this kind of broader American-style identity. Unlike the United States, which was forged out of shared ideals rather than shared genes (and thus ready to adopt any newcomers who accepted its values), Britain and many other European countries became multicultural before they had developed a philosophy of multiculturalism. "Multiculturalism as lived experience enriches our lives," wrote British author Kenan Malik. "But multiculturalism as a political ideology has helped create a tribal Britain with no political or moral center."

A little more than a decade ago, in the post-9/11 world, Britain's Labour government began an earnest effort to identify and promote that political and moral core by showing that there's more to being British than having a stiff upper lip. They examined the process of becoming a citizen, which had been nothing to write home about: "I sat alone in an office with a businesslike bureaucrat, who administered a brief oath to Her Majesty the Queen on a paperback Bible," remembered journalist Anne Applebaum of when she took British citizenship. "She asked me no questions about Great Britain, nor had I taken a citizenship test, as all would-be Americans have to do."

Britain introduced a citizenship test in 2005 as well as naturalization ceremonies where fledgling Brits echoed the Oath of Allegiance as they pledged "loyalty to the United Kingdom" and to "respect its rights and freedoms" as well as to "fulfil my duties and obligations as a British citizen." A government panel wrestled with the question of what a newcomer needed to know to be a modern multicultural Brit and came up with a test that mixed practical skills, historical knowledge and a little cultural know-how. It also provided a booklet of handy hints on how to manage the natives, including what to do if you spill somebody's drink in a pub. (Offer to buy another round.) Last year, an updated test was released, which might quiz you on anything from the name of the capital city (London) or Chaucer's work ("The Canterbury Tales") to how life peers get picked, and what happened in 1066 and all that.

The underlying message is clear: You don't have to be born here to be one of us. And that will be a lot harder to explain to prospective immigrants to England, Wales and Northern Ireland - or Engwalni, as some wags are calling the post-British region in an awkward attempt to create togetherness out of three distinct ethnic identities. Harder still in Scotland, which is building its national identity on ethnic separatism and cultural conformity.

Sellers, a dual British/U.S. citizen, is senior writer at The Washington Post magazine. She joined the magazine in 2014 after spending two years as the editor of the daily Style section, with a focus on profiles, personalities, arts and ideas.