Americans increasingly are calling themselves "unaffiliated" with any religion — or rejecting religion altogether — at a time when influential Republicans are leaning into Christian nationalism to shape public policies, a new survey finds.

Why it matters: The survey found that 26% of Americans now consider themselves unaffiliated with a religion. That's up 5 percentage points from 2013, and reflects a widening gap between how citizens and lawmakers see religion's role in society.

• The GOP is dominated by white evangelicals who have successfully pushed to limit abortion, ban books and restrict some LGBTQ+ rights. But the general public — especially younger Americans — is rapidly moving away from religions that endorse such policies.
• Just a slim majority of Americans (53%) now say that religion is important in their lives, down from 72% in 2013, the survey by the nonpartisan Public Religion Research Institute says.
• The findings suggest that Republicans who focus on evangelical priorities — such as former President Trump, who's now hawking Bibles, and House Speaker Mike Johnson (R-La.), who flies a flag favored by Christian nationalists outside his office — are preaching to a loyal but dwindling audience.

The big picture: Among Christian groups, Catholics as a whole continue to lose more members than they gain — and are seeing the largest declines in affiliation of any religious group.

• In 2023, 18% of white Americans said they grew up as Catholics, but one-third of them said they no longer identify as members of their childhood faith.
• 12% of Hispanic Americans said they grew up as Catholics; one-third of them also said they no longer identify as such.

Yes, but: The percentage of Americans who identify as white evangelical Protestants appears to have stabilized after years of decline.

• Black Protestants and Jewish Americans have the highest retention rates of all religious groups.

Overall, the survey found that one in 10 Americans in 2023 reported having grown up without a religious identity.

• Another 18% of Americans said they became unaffiliated after growing up in a particular religious tradition.

The intrigue: The jump in unaffiliated Americans comes as many say they no longer believe in their initial religion's teachings — or disagree with a religion's stance against LGBTQ+ people in particular.

• Among unaffiliated Americans younger than 30, "60% cite the treatments of LGBTQ as a reason they stop going to church," PRRI CEO Melissa Deckman tells Axios.
• The rise of Christian nationalism and GOP state legislators pushing anti-LGBTQ+ laws also is leading young people to turn away from organized religion, she said.
• Members of Congress are more Christian — and more religious — than the American public by wide margins, according to an analysis of data reviewed by Axios last year.

Methodology: PRRI conducted the survey on Nov. 16 and Dec. 7, 2023. The poll is based on a representative sample of 5,627 adults (age 18 and older) living in all 50 states and the District of Columbia.

• Among those, 5,303 are part of Ipsos' Knowledge Panel® and an additional 324 were recruited by Ipsos using opt-in survey panels to increase the sample sizes in smaller states.
• The margin of sampling error is ±1.79 percentage points at the 95% confidence level, for results based on the entire sample.