Countries with governments that favor Christianity cause their residents to become less attached to their faith, which could eventually lead to a decline in the percentage of the population that identifies as Christian, two social science researchers have suggested, based on an analysis of 166 countries.

The seemingly paradoxical relationship helps explain large declines in the number of people across the U.S. and Europe who identify as Christian, the researchers wrote in a Sociology of Religion paper published April 7. 

"When certain faith traditions receive privileges from the state, they end up losing their fervor," co-authors Nilay Saiya and Stuti Manchanda of Nanyang Technological University, in Singapore, told The Academic Times. "This has certainly been the case in Europe and increasingly in the United States."

By contrast, governments that actively persecute Christians may cause adherents to become more attached to their faith, cementing Christianity's role within that country, Saiya and Manchanda wrote.  

A third type of government attitude toward Christianity, in which governments encourage religious diversity without favoring any religion in particular, also strengthens the Christian population by forcing its members to compete with other faiths, the researchers said. 

In the U.S., no religion is ostensibly favored by the state. But 88% of the members of Congress identified as Christian in 2019, according to the Pew Research Center, and the religion has been wielded by politicians, especially on the evangelical right, as a political tool for decades.

Saiya and Manchanda said Christianity's dominating role in U.S. politics may have the effect of pushing people away from the church. The percentage of U.S. adults who identify as Christian has declined from 77% in 2009 to 65% in 2019, according to Pew. 

"The intertwining of religion and politics in the U.S. repels people from Christianity," Saiya and Manchanda said. "These people see the Christian faith as supporting a certain kind of politics they personally disagree with. As a result, politicized Christianity is able to appeal to an increasingly narrow group of individuals as it drives liberals and moderates away from the church." 

In order to test the relationship between government attitudes toward Christianity and growth or decline of the religion, the researchers ran a series of statistical models using data from 166 countries, 96 of which were majority Christian and 69 of which were minority Christian. Saiya and Manchanda measured religiosity of countries with data from 2010 to 2020 from the Pew-Templeton Global Religious Futures Project and measured discrimination using data from Bar-Ilan University's Religion and State Project, which tracks 27 types of discrimination, harassment and violence against minority religions across nations. 

Across four statistical models, countries treating Christians favorably at the expense of other religions were associated with a statistically significant decline in the population growth rate of Christians within those countries, the researchers found; it was statistically significant at the 1% level in one model and at the 0.1% level in three others. A one-unit increase in a country's "minority religious discrimination score" — indicative of favorable treatment of Christians at the expense of other religions — was associated with a deceleration in the growth rate of that country's Christian population by 2% to 4%. 

"One thing we found especially interesting is how strong the relationship between Christian privilege and declining Christian populations is," Saiya and Manchanda said. 

The researchers ran four additional statistical models that tested how discrimination against Christians affected the growth of Christianity. It was statistically significant at the 10% level in two models but was not statistically significant in the other two. 

"While the lack of statistical significance means we cannot confidently conclude that Christianity experiences growth in these countries, we can safely infer that it does not generally experience decline," the researchers wrote. "In short, unlike contexts of privilege, environments of persecution appear not to hinder Christian growth." 

An example of a country where Christianity is flourishing despite persecution is China. Even as the state has confiscated bibles, removed crosses from churches and locked up pastors, Christianity has continued to grow, The Economist reported last year. China now has an estimated 60 million Christians, and the number of Protestant Christians has nearly doubled over the past decade, according to the newspaper; China now has a larger Christian population than France or Germany. 

"Perhaps China provides the most startling example of the paradox of persecution in the modern world," Saiya and Manchanda wrote. 

The researchers said they focused exclusively on Christianity because it is the world's predominant religion, and Christian communities can be found in every country.

"We fully expect, though, that the relationships we find for Christianity would also apply to other faith traditions," they said. "A natural follow-on question is if our findings apply to Islam."

The study, "Paradoxes of pluralism, privilege, and persecution: Explaining Christian growth and decline worldwide," published April 7 in Sociology of Religion, was authored by Nilay Saiya and Stuti Manchanda, Nanyang Technological University.