Countries are not set in aspic, they constantly change, evolve and acquire new layers. Britain's identity is a mixture of Roman, Celtic, Anglo-Saxon and Norman - the first and last of which inserted themselves into the national fabric in distinctly more violent and disruptive fashion than Asians and blacks are doing now. Tebbit's vision is of a Britain where the church clock is for ever at ten to three, whose inner cities are unstained by crime, where everyone knows their place beneath the law and God.
One may wonder, too, about Tebbit's opinion of the US, a model lauded so often and so loudly by his liege-lady, Margaret Thatcher, but whose fault lines mostly spring from the uniquely multicultural character of its society. Unlike Britain's voluntary immigrants from the Caribbean, America's black community has every right to disown all things American: "We didn't land on Plymouth Rock, Plymouth Rock landed on us," said Malcolm X, a forefather of Louis Farrakhan's Nation of Islam, which a couple of years ago set white America's nerves on edge with the Million Man March in Washington DC. In America, too, so great is the Hispanic influx that many demand special laws to defend the status of English as official language. Only in America, too, is the tiniest slur, real or imagined, capable of having an entire ethnic group up in arms - or rather of propelling it to the law courts.
And yet America flourishes, not so much in spite of as because of multiculturalism. In America, to the country's great advantage, multiculturalism ensures very few people know their place. Multiculturalism is at the heart of America's tensions, but also of its vitality. America has its Tebbits - the Pat Buchanans and the redneck militiamen who rail against gays and foreigners of every hue, and believe the United Nations and the World Trade Organisation are plotting to turn the country into a vassal state. The notion is as absurd as Tebbit's suggestion that Britain could become another Yugoslavia.
Indeed, in matters multicultural, Britain in some respects is doing better than America. Race relations are palpably more relaxed here. Maybe it is another case of British muddling through, reflecting both the fact that we do not have an education system that force-feeds our "national heritage" as vigorously as Tebbit would like, and our ability to laugh at ourselves.
Or take France. Confident of the power of its rayonnement culturel, it long considered itself multicultural. Today, however, for its population of North African origin, "Frenchness" is increasingly less beacon than straitjacket. France is caught in a vice, between a minority that cannot be fully assimilated, and nationalist politicians, led by Jean-Marie le Pen, who are more numerous and more extreme in their views than Tebbit and their other counterparts in Britain.
But there is a deeper truth. In countries around the world, the divided loyalties so lamented by Tebbit abound, deriving from race, skin, faith or language. As America shows, they need not be a recipe for disaster. Rather, as attested by the tragedy of 20th century German Jews - in all but one fatal respect more German than the Germans - the worst trouble comes when the state deems those loyalties mutually incompatible.
Tebbit may have a point when he argues that beyond small groups such as club, family or gang, humans cannot relate directly to each other without overriding standards or beliefs in common. Without such glues of language, national heritage and so on, a country ceases to be a nation or a society, just "a population living under the same jurisdiction".
To which one may answer first: and what is wrong with this minimalist definition of statehood? Lack of a common faith or language does not mean all roads lead to Bosnia. True, there are multicultural mismatches like Canada which, if God rather than messy events shaped history, would surely be two countries. But Switzerland, boasting three languages and much cantonal tribalism, is doing very nicely. Belgium, despite the odd ruction, functions well enough.
Second, Tebbit's argument is defeatist. If the majority's heritage and culture are sufficiently attractive, the minority will embrace them alongside their own, and sometimes, gradually, in substitution for their own. In the process the dominant culture will be subtly altered. By and large this is what has happened in America, and the phenomenon is to be observed here. What, after all, is more "British" than the Indian take-away?
Third, like it or not, multiculturalism's advance is irresistible. It's not just the sheer impossibility of undoing what is already done. Mixed marriages will increase. Easier travel, the growth of supranational institutions like the European Union, the communications revolution, the Internet, and the babel of a myriad of competing media outlets, representing every ethnic and cultural group - all are spoons to stir the global cultural pot, reaching effortlessly over the borders so cherished by Tebbit.
For proof, there is sport, which has largely replaced the old-fashioned instruments of monarchy, war and diplomacy as a prism for national loyalty. For me and maybe millions of others, a victory by an Italian, Spaniard or Swede in the recent Ryder Cup was as welcome as one by an Englishman, as long as an American was on the receiving end. And as an Arsenal supporter, I would look most benignly on a Dutch victory over Glenn Hoddle's team if a couple of Dennis Bergkamp goals were responsible.
So much, too, for the celebrated Tebbit "cricket" test - that you can't be English if you don't support the national cricket team. What about Nasser Hussain, Mark Ramprakash, the Hollioakes, Devon Malcolm, Andy Caddick - colonials all of various hues? Support the team? They are the team. Yesterday, typically, Norman Tebbit would yield no ground: "If a society does not integrate, it will tend to disintegrate ... It will be a little while before we look at the Notting Hill Carnival the same way as we do Morris dancing." But one thing is certain. Sooner, rather than later, we will.