How strongly do Americans support religious rights? Depends on the religion.

Some 8 in 10 Americans say it's important for religious freedom to be protected for Christians, a new poll finds. That number drops to 6 in 10 when it comes to protecting the religious rights of Muslims.

Religious liberty is a key principle of American democracy, but public support for individuals’ right to exercise that freedom still varies by which religion they practice.

In a new poll, 82 percent of Americans say it’s very or extremely important for Christians to be allowed to practice freely, compared with 61 percent who say the same for Muslims. (For Jews, the figure is 72 percent; for Mormons, 67 percent; and for people with no religion, 63 percent.)

The gaps in part reflect the fact that the United States has always struggled to live up to the ideals in its Constitution. But they also raise the question of whether the relative success of America’s experiment with religious diversity can survive for future generations when 4 out of 10 don’t believe strongly in protecting the rights of all.

“On one hand, it’s heartening that a majority of American people understand that religious liberty is for everyone…, [but] the goal is to have enough in support of this arrangement that it actually works,” says Charles Haynes, director of the Religious Freedom Center of the Newseum Institute in Washington.

“If we lose the hearts and minds … on religious liberty, we lose what’s enabled us to live with these differences” and maintain peace better than most, if not all, other nations facing religious divides, he says.

The results may have been influenced by the timing of the poll, conducted by the Associated Press-NORC Center for Public Affairs Research between Dec. 10 and Dec. 13, not long after attacks in Paris and San Bernardino sparked rising anxiety about Islamic State terrorism. The same poll shows an increase over time in Americans’ concern that they will be the victim of a terrorist attack.

“These numbers seem to be part of a growing climate of anti-Muslim sentiment in the United States,” Madihha Ahussain, an attorney for Muslim Advocates, a California-based civil rights group, told the Associated Press. “This climate of hatred has contributed to dozens of incidents of anti-Muslim violence in recent weeks.”

The poll’s new question on religious liberty yields “important data, but it’s also important to ask it in calmer times … to establish a trend,” says Jennifer Benz, deputy director of the AP-NORC Center.

The poll of 1,042 adults was conducted online and by phone using a sample designed to represent the US population. The margin of error is plus or minus 3.9 percentage points.

A slight majority of Americans – 55 percent – say the government is doing a somewhat or very good job at protecting the freedom of religion.

Ever since the Puritans arrived in the name of religious freedom, there’s been a selective application of that idea in practice.

“Liberty for me but not for thee is a very longstanding and widespread fallacy,” writes Douglas Laycock, a scholar of religious liberty at the University of Virginia School of Law, in an e-mail to the Monitor. “The Puritans came to America for religious liberty, but immediately decided that they meant religious liberty only for themselves…. There were huge fights between Catholics and Protestants in the nineteenth century, and outright persecution of Mormons. Now Jews are clearly inside the circle of religious liberty, and Muslims, Buddhists, Hindus, and nonbelievers are on the perimeter, protected in law but not so much in public opinion.”

Conservative Christians also believe their rights are being infringed upon, by being forced, for instance, to offer wedding-related services to same-sex couples.

But some conservative Christians, as well as some politicians, are capitalizing on fears of terrorism to push a longstanding agenda opposing Islam as what they believe to be an inherently threatening religion, Mr. Haynes says.

The poll finding that nearly 40 percent of Americans don’t think it’s important to protect Muslims’ religious freedom doesn’t come out of thin air, Haynes says. “Many in America have been educated about Islam as a dangerous, violent religion,” and those spreading that message have spent tens of millions of dollars to do so in various churches and tea party conventions, he says.

The poll indicates some differences by political affiliation.

Independents are the least likely to say protecting religious freedoms is extremely or very important (69 percent of them say it is regarding Christians, and 49 percent say so regarding Muslims).

Among Republicans, 88 percent place high importance on protecting religious freedoms of Christians, compared with 60 percent regarding Muslims – a 28-point gap. Among Democrats, the figures are 83 percent and 67 percent respectively – a 16-point gap.

Overall, 8 out of 10 Americans said it was important or extremely important for people like themselves to be able to exercise religion freely.

But for religious liberty to work in practice, Haynes says, it would be more encouraging to see high poll numbers reflecting the idea that “I am in favor of religious liberty for others, including those groups I don’t like, including those groups I disagree with.”