Kaufmann has argued that in the Western world, as the second demographic transition occurred during the 1960s, people began moving away from traditional, communal values towards more expressive, individualistic outlooks, owing to access to and aspiration for higher education.

The first demographic transition resulted from falling fertility due to urbanization and decreased infant mortality rates, which diminished the benefits and increased the costs of raising children.

Because children of immigrants in Europe tend to be about as religious as they are, this could slow the decline of religion (or the growth of secularism) in the continent as the twenty-first century progresses.

Research by Kaufmann and political scientists Roger Eatwell and Matthew Goodwin suggests that such a fast-paced ethno-demographic change is one of the key reasons behind the public backlash which has manifested itself in the form of national populism across rich liberal democracies, an example of which is the 2016 United Kingdom European Union membership referendum, which led to a UK majority vote to leave the European Union.

Children of immigrants tend to be about as religious as their parents and consider their religion to be a marker of their ethnic identity, thereby insulating themselves from the secularizing forces of the host society.

[11] In Finland, the Laestadian Lutherans maintained a significant fertility advantage over the average Finn during the mid- to late-1980s, 5.47 compared to 1.45, despite seeing declines during the course of the twentieth century.

[11] Similarly, he predicted that Catholicism will become the largest religion in the United States by 2040 despite considerable losses to secularization and conversion to Protestantism, thanks in no small part to the fact that Latino Catholics had a fertility rate of 2.83, compared to the national average of 2.03 in 2003.

[12] Kaufmann reported that in the United States, religious conservatism and participation play a key role in raising the relative level of fertility.

He rejects the conventional view that this is due primarily to comparatively low fertility rates, large-scale international migration, and the growth in cultural prominence of ethnically diverse newcomers.

[18] Historically, the early Anglo-Protestant settlers in the seventeenth century were the most successful, creating numerous surviving written records and political institutions that last till this day.

Commitment to the ideals of the Enlightenment meant that they sought to assimilate newcomers from outside of the British Isles, but few were interested in adopting a pan-European identity for the nation, much less turning it into a global melting pot.

While the more traditionalist segments of society continued to maintain their Anglo-Protestant ethnocultural traditions, universalism and cosmopolitanism started gaining favor among the elites.

[18] In this 2010 book, Kaufmann argued that the answer to the question raised in the title is in the affirmative because demographic realities pose real challenges to the assumption of the inevitability of secular and liberal progress.

Highly religious groups tend to isolate themselves from the secularizing effects of modern mainstream Western society, making it more likely that the children will retain their parents' faiths.

He told Mercator Net that the only way to buckle the trend involves "a creed that touches the emotional registers", which "can lure away the children of fundamentalists" and "a repudiation of multiculturalism."

However, Kaufmann rejected the increasingly popular notion that Islam will become the dominant religion in Europe by the end of the twenty-first century; rather, he suggests that Muslims will stabilize at around a fifth of the European population by 2100.

[21] In the late twentieth and early twenty-first century, Kaufmann argues that, unlike Japan, the nations in Western Europe, North America, and Oceania did not experience a population decline despite having mostly sub-replacement fertility.

[13] The title of the 2018 book encodes Kaufmann's predictions that, as a result of international migration, Western countries will become ever more ethnically diverse and a growing number of people will be of mixed heritage.

For Kaufmann, one of the major schisms in the political landscape of the West at the time of writing is due to factions that want to speed up this process and those who want to slow it down.

These norms have prevented mainstream politicians and political parties from responding to the concerns of large swathes of the voting population, giving nationalist populists an opportunity to rise to the front.

[23] Despite an emphasis on white reaction to demographic change and mass migration, Kaufmann gave Proposition 187, a 1994 California ballot initiative aimed at preventing taxpayers' money from going to illegal aliens, as an example of opposition from non-whites.

Kaufmann is methodologically catholic and draws on a rich range of different resources to examine and interrogate evolving white identity politics."

"[31] Sociologist John Holmwood argued that the lack of any discussion of "settler colonialism or of the place of first Nation populations and enslavement of African Americans and Jim Crow segregation in the USA" represent "serious – in fact, fatal – omissions in a book concerned to rehabilitate symbols of white identity."