DES MOINES — Their numbers are declining, and public opinion is parting from some of their most deeply held views.

Many conservative Christian Americans feel like they — or their beliefs — are under attack.

Whether over same-sex marriage, reproductive rights or religious liberty, many conservative Christians think they are being persecuted for their beliefs by liberals and the government. In the lead-up to the Iowa caucuses, 2,500 people attended a religious freedom event in Des Moines, hosted by eventual caucus winner Ted Cruz.

Cruz declared at the event, “There is a war on faith in America today.”

And many conservative Christians are concerned this year they also have lost the ability to back a presidential candidate who embodies their values.

DECLINING NUMBERS

Between 2007 and 2014, the number of self-identified Christians in America fell 5 million, from 78.4 percent of the population to 70.6 percent, according to the Pew Research Center. The sharpest drops came among mainline Protestants and Catholics.

In that same time, according to Pew, the share of Americans who consider themselves unaffiliated to a specific religion grew sharply, from 16 percent of the population to 23 percent. The share of Americans who belong to non-Christian faiths also increased.

As of 2014, there were more unaffiliated Americans than Catholics (20 percent of the population) and nearly as many evangelical Christians (25 percent).

But Christians comprise 77 percent of the population in Iowa, and leaders say the faith-based voting bloc still has a relevant voice in the state.

“I think here in Iowa they certainly are strong and alive yet,” said Steve Scheffler, president of the Iowa Faith and Freedom Coalition, a nonprofit organization that formerly was called the Iowa Christian Alliance.

Scheffler also is one of Iowa’s two Republican National Committee members; the other is Tamara Scott, an advocate for conservative social causes.

Bob Vander Plaats, president and CEO of the Family Leader, a Christian advocacy organization, said Cruz’s victory in the caucuses showed faith-based voters still carry weight among Iowa conservatives.

Vander Plaats supported Cruz’s presidential campaign.

PUBLIC OPINION DIVERGING

In addition to their falling numbers, conservative Christians feel on the defensive because of shifting public opinion on key social issues.

A prime example is support for legal same-sex marriage, which increased from just more than 30 percent in 2004 to more than half of Americans in 2014, according to Pew.

Vander Plaats, however, said he thinks there remains strong support for conservative public policy on those issues. He said that’s why conservatives are focused on the U.S. Supreme Court vacancy as a voting issue in the presidential election, because it appears the next president will have an opportunity to make at least one and possibly multiple lifetime appointments.

Vander Plaats said traditional marriage, abortion and religious liberty still are strong motivators for conservative Christian voters.

“I think religious liberty issues are heightened … not waning in importance,” he said.

Even as the number of Christians declines, more Christians want religion and the church to play a larger role in politics, according to Pew.

In 2014, for the first time in eight years, more Americans thought churches and houses of worship should express their views on social and political issues (49 percent) than those who thought churches should keep out of politics (48 percent).

And the share of people who think churches should come out in favor of one candidate over another increased 8 percentage points between 2010 and 2014.

PLACING FAITH IN TRUMP

Many conservative Christians who have long voted Republican are conflicted with their choices in this year’s presidential election, not yet comfortable supporting the GOP’s presumptive nominee, billionaire businessman and reality TV star Donald Trump.

Trump, who finished second to Cruz in the Iowa caucuses, has attempted in speeches to play up his faith.

But he also has made statements that have given pause to conservative Christians. At an event in Iowa, he said he has never asked God for forgiveness and said of Communion, “I drink my little wine” and “have my little cracker.”

In a national interview, when asked for his favorite Bible passage, Trump declined to name a specific verse.

Trump was seen as the least religious of the leading presidential candidates, including Democrats Hillary Clinton and Bernie Sanders, in a national Pew survey conducted in January. Three of every five adults surveyed said they think Trump is “not too” or “not at all” religious.

Only 30 percent of adults surveyed said they think Trump is “very” or “somewhat” religious, compared to 68 percent for Ben Carson, 65 percent for Cruz and 48 percent for Clinton.

And while many evangelical voters surveyed by Pew said they think Trump would be a “good” or “great” president, almost 30 percent said he would be a “poor” or “terrible” president, more than double the share who said the same about Cruz.

Vander Plaats said he thinks those hesitant conservative Christian voters’ feelings about Trump can be divided three ways: those who will not vote for him and will simply avoid the presidential race, those who will support him because of the Supreme Court issue or a desire to defeat presumptive Democratic nominee Hillary Clinton, and those who are biding their time, hoping eventually to see in Trump a candidate they can support.

Vander Plaats said he considers himself in the wait-and-see category.

“Now that Trump is the presumptive nominee, they’re watching him to see what kind of nominee he is going to be,” Vander Plaats said. “Is he going to champion Hillary Clinton’s values, but to a lesser degree? If he does that, then I think you’re going to see a lack of enthusiasm.”

For Scheffler, the matter is simpler. He said he thinks for any of issues conservative Christian voters may have with Trump, the potential for another four years with a Democrat in the White House — and what that could mean for the future of the Supreme Court — should be sufficient motivation.

“From over-regulation, to national security, to Supreme Court justices, to promotion of life issues … the list goes on and on,” Scheffler said. “With Hillary Clinton, it’s totally predictable: It’s going to be anything but what conservatives want.

“She would be an absolute catastrophe and an absolute disaster for conservatives,” he said. “(Trump) may not be perfect, but the bottom line is he’s the (Republican) nominee, and he’s far, far better than her.”