Republican presidential candidate Ted Cruz speaks in Des Moines on Friday. (Mark Kauzlarich/Reuters)

When Sen. Ted Cruz spoke during Sunday service a week ago at a Baptist church here, it was difficult to tell whether he was preaching or practicing politics.

Pacing on an altar in front of a white-robed choir, Cruz led the congregation in a prayer for the victims of the Paris terrorist attacks — and then launched into a sermon-like speech that pivoted into politics.

“If 10 million more evangelical Christians show up in November 2016, we’re not going to be staying up until 3 in the morning wondering what happened in Ohio or Florida,” he said. “They’ll call the election at 8:35 p.m. That’s what 10 million more evangelical Christians at the polls will do.”

The Republican presidential candidate has spent his entire campaign — launched at Liberty University, the Christian school founded by Jerry Falwell in Lynchburg, Va. — courting the support of evangelical Christians. Yet his effort has intensified in recent weeks — a sign not only of the looming proximity of the first nomination votes in such early states as Iowa and South Carolina, but also of the fact that he still hasn’t made the sale with the voters he needs to win the nomination.

Cruz still trails neurosurgeon Ben Carson, a favorite of faith-based voters, nationally as he has for months. Cruz’s plan is multipronged, based in part on the idea that Carson, who has faced scrutiny in recent weeks for a lack of foreign policy knowledge and a personal story sometimes inaccurately remembered — will stumble.

Although Carson has remained strong, Cruz has made gains in polls and has attracted support from several key evangelical leaders both nationally and at the grass-roots level. Cruz is attempting to draw a contrast between the two candidates by highlighting the religious-liberty cases he fought as a lawyer, his attempt to defund Planned Parenthood, his calls for a robust response to the Islamic State and his support for Israel.

According to a new Washington Post-ABC News poll, Carson remains firmly in second place nationally behind Donald Trump and with the same level of support — 22 percent of likely voters — that he held a month ago.

Cruz’s campaign strategists, meanwhile, said the senator from Texas has inherited support from religious supporters of Wisconsin Gov. Scott Walker, who dropped out of the race in September, and that the same will happen with backers of Louisiana Gov. Bobby Jindal, who pulled the plug on his campaign last week. After that? Carson.

In fact, Carson and Cruz are regular neighbors on the campaign trail — illustrating how much they are targeting the same voters. The two have circled each other multiple times in the past week in their hunt for Christians’ support. They appeared at Bob Jones University in Greenville, S.C., on back-to-back days — and then on the same stage Friday at a conservative Christian forum in Des Moines.

Carson spokesman Doug Watts said the candidate has long been involved with the faith community and is focusing his efforts on the grass roots.

“When you speak to the evangelical voter, you’re going to find they’ve known of Dr. Carson for a very long time,” Watts said. “I think that’s a very big difference between him and someone who is relatively new on the scene.”

In the past week, Cruz has made an even more overt play for many of the faith-driven voters who are supporting Carson, including announcing his immigration plan at an Orlando church and trying to reach the large concentration of faith-based voters here in South Carolina.

“Some pastors, you may be thinking, ‘Well, over half of Christians aren’t voting, but not in my church,’ ” Cruz said in Greenville. “You sure? How sure are you?”

Cruz’s evangelical strategy is an unconventional one — paired with a bid for libertarian and tea-party-affiliated voters as well. He is attempting to coalesce national support early, a strategy he thinks will propel him to strong finishes in Iowa and the South, and ultimately to the nomination. Also unconventional is Cruz’s view that the bid for evangelicals will be just as effective in the general election, when a broader, more moderate electorate will be weighing in.

For months, Cruz; his wife, Heidi; and three people on his campaign dedicated solely to the task have reached out to faith leaders active in the grass-roots movement and on the state and national level. The campaign has secured the support of about half of the 400 or so evangelicals nationwide whose support advisers say is critical. This week, Cruz launched a national prayer team, inviting supporters to participate in a 20-minute prayer call each Tuesday.

It will “establish a direct line of communication between our campaign and the thousands of Americans who are lifting us up before the Lord,” a statement said.

The campaign is also putting faith-outreach leaders in all 99 of Iowa’s counties and South Carolina’s 46. Cruz drew about 2,500 people to a religious liberty rally in Des Moines in August.

Cruz has a potent surrogate in his father, a minister, who has spoken to pastors around the country on behalf of his son. Rafael Cruz earlier this year blitzed across Iowa, hoping to lock down support in the nation’s first voting state, and has also been deployed across the South, a region where Cruz hopes to gain big victories during primaries in March.

“The word of God says if the foundation is being destroyed, what can the righteous do?” Rafael Cruz said at a meeting of pastors in the U.S. Virgin Islands earlier this year. “We’ve seen an erosion of our foundations in the United States.”

The senator talks about how his father left him and his mother and returned after finding God; Cruz told a story Friday in Des Moines about how he had sent both of his parents pages of Scripture as they were on the brink of divorce later in life, hoping to change their minds. The divorce proceeded regardless.

He also regularly draws a distinction between himself and other faith-based candidates by portraying himself among evangelicals as one of them. Literature distributed at his event here noted that he was the valedictorian of his class at the Second Baptist high school in Houston. He is introduced as a preacher’s kid. He repeats over and over the assertion that he has spent his career fighting for religious liberty.

“If the body of Christ rises up as one and votes our values, we can turn this country around,” Cruz told attendees Friday night at the Family Leader’s forum in Des Moines.

Cruz specifically cites two successful court cases as evidence of his commitment to religious liberty. In one he argued as solicitor general of Texas to keep a Ten Commandments monument on the capitol grounds. The other, which he participated in while in private practice, concerned a cross at a veterans’ memorial in the Mojave Desert.

The candidate also seized on three issues important to evangelicals: the Supreme Court’s ruling legalizing same-sex marriage nationwide, the saga of a Kentucky clerk jailed for not issuing same-sex marriage licenses and videos purported to show Planned Parenthood officials discussing the sale of fetal tissue.

Cruz used the Planned Parenthood videos to kick his evangelical outreach into high gear, taking a lead role in a 50-state campaign that sought to end taxpayer support for Planned Parenthood by having pastors mobilize churchgoers to call their elected officials in Congress.

Cruz also argues that Christians are particularly under attack by President Obama. He said last week that he believes Syrian refugees who are Muslim should not be allowed into the country — but that Christians should, because there is “no meaningful risk” of Christians committing terrorist acts. He has assailed Obama’s handling of the Islamic State in the wake of the Paris terrorist attacks, something the campaign believes will appeal to evangelical voters.

“The federal government wages a daily assault on life, on marriage, on religious liberty. It’s because Christians are not standing up for our values,” he said at Bob Jones.

Cruz’s hard line is resonating with voters such as Lois Howell, a missionary who lives in Honduras but votes in Florida and has two daughters at Bob Jones. She believes evangelical Christians are ready to fight back against social changes.

“What resonates with us is that we have felt the ‘Oh, you’re stupid evangelicals, you don’t know anything, you hate people,’ ” she said. “They hate God, and they take it out on us.”

Cruz, she said, is “one of us.”

Sean Sullivan contributed to this report from Des Moines.