The tide of people moving across the world as immigrants or refugees has sparked concern in the developed world – from the United States to Europe to Australia. In particular, the ethnic, linguistic and cultural background of the many seeking asylum or economic opportunity has triggered debates, especially in rich countries, over the benefits and the costs of growing diversity at home.

Unease over the cultural, not only economic and security, ramifications of immigration has been a key factor in the United Kingdom’s Brexit vote, plans for a wall along the US-Mexican border and the rise of right-wing populist parties in Europe.

“Being one of us” has become highly politicised. National identity – what it means to be truly American, German, Japanese or citizen of any other nation – varies sharply among nations, political parties and generations, suggests the Pew Research Center as part of its Global Attitudes cross-national studies. Against the backdrop of sometimes intense nationalist rhetoric, it might be assumed that many in developed countries link national identity with one’s place of birth. At a time when the number of people living outside their places of birth has reached more than 200 million – the size of a populous country like Brazil – the issue of identity is sparking acute political debate.

Sense of belonging: Place of birth is not an essential feature for national identity compared with other factors, according to Pew Research surveys in selected nations

A Pew Research Center survey finds that people generally place a relatively low premium on a person’s birthplace: Only 13% of Australians, 21% of Canadians, 32% of Americans and a median of 33% of Europeans suggest that it is very important for a person to be born in their country in order to be considered a true national.

There are exceptions – Hungary, 52%; Greece, 50%; and Japan, 50% – where about half the public considers birthplace to be very important. But in other nations – countries where there have been visible backlashes against refugees including Germany, 13%; Australia, 13%; and Sweden, 8% – few people make a strong connection between the locale of one’s birth and national identity.

What counts

While many in the countries surveyed are open to those born elsewhere being part of “the nation,” acceptance comes with certain requisites. Majorities in every country surveyed say it is very important to speak the dominant language to be considered a true national. This includes a median of 77% across Europe and strong majorities in Japan and the US, 70%; Australia, 69%; and Canada, 59%.

In addition, sharing national customs and traditions is very important to many people’s sense of “being one of us.” Roughly half or more link adoption of local culture to national identity in Canada, 54%; Australia, 50%; and Europe, a median of 48%. Somewhat fewer Americans, 45%, and Japanese, 43%, say cultural traditions are essential to being a true national.

Even within developed countries, views on national identity differ, often along partisan or ideological lines.

In the United States, 83% of Republicans say language proficiency is a very important requisite for being truly American. Fewer Democrats, 61%, agree. Among Republicans, 60% say that, to be considered a true American, it is very important that a person share US culture. Only 38% of Democrats share that opinion.

Notably, there is not much partisan difference about the link between the land of one’s birth and US national identity. Roughly a third of Republicans, 35%, and Democrats, 32%, say being born in the United States is very important.

Views of what constitutes national identity also divide publics along party lines in some European countries. In the United Kingdom, 73% of those who have a favourable opinion of the right-wing UK Independence Party, UKIP, say adhering to British culture is very important to being British. Just 44% of those who have an unfavorable view of UKIP agree.

In France, sharing French customs and traditions is tied to national identity for those who have a favorable view of the right-wing, populist National Front – 65% say it is very important. Just 39% of those who hold an unfavorable opinion of the National Front strongly link culture to being truly French. There is a similar 24-percentage-point difference on the importance of Swedish customs and traditions between sympathizers with the right-wing, populist Swedish Democrats and those who see them unfavourably.

And in Germany, a 22-point gap exists on the importance of culture between those who favor the Alternative for Germany party and those who don’t.

Ability to communicate: There's wide agreement in response to Pew Research surveys that ability to speak the national language is "very important" to belonging to a nation; Canadians were asked about "either English or French"

Ideological divide

In Australia, supporters of the Centre-Right Liberal Party and Centre-Right Labor Party, 79% and 68%, respectively, say it is very important to speak English to be considered Australian. Only a third of the Left-leaning environmentally oriented Greens agree. There is even greater partisan disparity on the importance of customs and tradition. Among Liberal Party followers, 63% suggest that adherence to Australian customs and traditions is very important to national identity while 44% of Labor Party supporters concur. Even fewer Greens agree at 15%.

In Canada, while majorities across all major parties say it is very important to speak either French or English, this sentiment is held most strongly by those supporting the Centre-Right Conservative Party of Canada, 68%, followed by those backing the Centre-Left Liberal Party, 59%, and those supporting the social-democratic New Democratic Party, 53%. More than six in 10 Conservatives, or 63%, suggest that a person must share Canadian customs and traditions to be truly Canadian. Fully 57% of Liberals agree, but only 46% of New Democrats share this view.

Sentiment regarding what defines national identity is also a generational issue, with the young placing far less emphasis than the old on culture and birthplace.

In the United States, 40% of people ages 50 and older are likely to say it is very important that a person be born in the country to be considered truly American while for only 21% of those from ages 18 to 34 feel this way.

In Japan, the generational divide is more pronounced: older Japanese are more likely than their younger counterparts to link national identity to birthplace by a 59% to 29% margin. Generational differences, though generally more modest, are also evident in Australia and Canada, 15 percentage points each, and across most European countries surveyed.

Across the countries surveyed, the generations differ even more sharply over the importance of national customs and traditions. In the United States, 55% of people ages 50 and older percent are far more likely than those ages 18 to 34 – at 28% – to say sharing such cultural elements is very important to being truly American. There is a similar 20-percentage-point generation gap in Canada, Australia and Japan. In Europe, a median of 37% of 18- to 34-year-olds suggest this aspect of national identity is very important, compared with 56% of those ages 50 and older.

At a time when economically developed countries are challenged by increased refugee and migrant flows – and fierce debates over immigration – relatively few survey respondents subscribe to birthright definitions of national belonging. This may be a hopeful sign for those seeking asylum or economic opportunity in a new country, as it’s possible to change how one speaks and acts, but not where one was born.

This article first appeared on Yale Global Online.