Identity does not change
According to Pew Research Center … issues about culture and identity continue to be at the center of heated political debates in the United States and Europe. The latter is a quote from their article Views About National Identity Becoming More Inclusive in U.S., Western Europe. [here]
In common with current practice, Pew continues to apply outdated subjective perspectives of identity in understanding the term. This is—by no means—a slur on the organisation. However, although the survey methods may be objective and beyond reproach, the gathered information represents subjective opinions obtained from selected populations at specific points in time. And Pew acknowledges the reality that opinions are subject to change. In fact, the whole article is about changing perspectives. Identity, on the other hand, does not change. It is who or what we are despite all changes over time.
Caricature of a nation
“Identity” is always associated with “sameness”, however tenuous that connection may be. So, when we talk about the national identity of any country, we always seek to know what is common and inherent in the population in question. What constitutes their essential national idiosyncrasies and characteristics? How would you recognise an American, British, Scottish or French citizen? In former times it was common to epitomise the people of different nations with simple icons like the British gentleman in a bowler; the kilted Scotsman; the Dutch lady with a Volendam hat; the kimono dressed Japanese and so on.
Some say that when you are in a country for a week you get a good idea about what constitutes the peculiarities of its people. When you are there for a prolonged period your initial impressions melt into confusion and it is extremely difficult to make any generalisations. Today we know too much to represent people by a single symbol.
Unfortunately, we have not changed our language to suit. To talk about “national identity” as if it were a single verbal icon is as irrelevant as applying the cartoon character of a man in a beret and striped shirt to represent a Frenchman. Use of the term “national identities” is a possible way out. Or is it? Applying this approach initiates the drift towards the division of a country into groups of people who are the same; or at least share similar characteristics.
The ultimate division in humanity is the individual, which is based on his or her unique genome. This implies that—strictly speaking—we can never create unique divisions in a population outside the individual. According to human genetics, the differences that we observe across the entire spectrum of living people are one of grade rather than essence. And though it may be helpful to divide populations into categories to study human behaviour, the groupings do not constitute separate “identities”. This holds true irrespective if we consider study-based sets developed on selected traits or the population of a whole country. Therefore, the word “identity” cannot be used in the context of an entire nation.
Some may react and say: Come on! This is pedantic. We all know what we mean by “national identity”.
But if it were so clear, then why would identity be at the centre of heated political debates in the West? Identity is categorically ambiguous. It has been described as a fuzzy concept; a vague concept; a term that has no unique definition; a word that is open to interpretation. Indeed, it is our ability to employ a range of meanings to the term that is the major cause of contention. If all disciplines stringently apply the objective (universal) paradigm of identity [here] this problem will be solved.
Returning to the title of the Pew article: If it is not about National Identity, what is it about? It is here that Professor of Sociology Rogers Brubaker of the University of California, and historian Frederick Cooper of the University of Michigan come to the fore. In their article Beyond “Identity” (2000) they boldly recommend casting the word aside and parcelling out the work which it currently does, to three groups of meaning: 1. identification and categorisation; 2. self-understanding and social location; and 3. commonality, connectedness, groupness. 
In other words, the Pew article refers to views about national perspectives, or how people of specific nations see and express themselves. “National identification” or other equivalent term may apply; but not “national identity”. Whilst such expressions may not flow as easily as the latter, they are more meaningful.
The adoption of the objective paradigm of identity not only removes a meaningless word, it frees us—psychologically—from perpetual nagging questions about what permits the people of one nation to qualify as “a people”. Such questions can only be answered descriptively and in very general terms. But it is naïve and futile to expect to derive “identity” from a group of people by asking for opinions of themselves.
Clan Sutherland (MacIan) Wikimedia Commons [here]
 Brubaker, R. and Cooper, F. 2000. Beyond “Identity”. Theory and Society. Vol. 29: 1-47.