Republican presidential candidate Ted Cruz (R-Tex.) speaks to the media during a campaign stop on Dec. 20, 2015, in Trussville, Ala. (Brynn Anderson/AP)

Conservative Christian activists whose support has been hotly pursued by Republican presidential candidates have begun to quietly coalesce around Sen. Ted Cruz — a major boost for his efforts to present himself as the leading challenger to front-runner Donald Trump.

Members of this core GOP constituency have long been torn between several favorites in the party’s crowded field. But many organization leaders have decided in recent days to line up behind Cruz (Tex.) because they consider him the best-funded and most electable social conservative in the race, according to several participants in the discussions.

He won the backing of a key evangelical coalition after a secret Dec. 7 meeting in which top national activists agreed to roll out a stream of endorsements, many timed for maximum impact between now and Super Tuesday on March 1, when a dozen states will hold primaries or caucuses. Eight of those states have significant evangelical populations, and Cruz is targeting them in hopes of emerging March 2 with the highest delegate totals of any candidate.

Since the Dec. 7 meeting, endorsements have been announced by influential figures such as James Dobson, a radio host who founded Focus on the Family; Brian Brown of the National Organization for Marriage; and Bob Vander Plaats, head of the Iowa Family Leader organization.

The next gathering will take place a few days after Christmas at a remote ranch in central Texas, where Cruz, his wife and several key financial backers will visit with some of the country’s most prominent evangelical leaders for private conversations and a public rally.

In this ad, Republican presidential candidate Ted Cruz talks about stopping illegal immigration and "securing our borders." (Ted Cruz/YouTube)

Some of the 100 or so leaders flying to the ranch, owned by conservative billionaire Farris Wilks, are still considering other candidates, including Sen. Marco Rubio (Fla.), who also is maneuvering to be the Trump alternative. But in recent weeks, Cruz has outpaced his rivals in the race to line up the support of religious conservatives.

Although Rubio has stepped up his courtship, activists say he is being hindered by a relatively late start. He has been warmly received but also has encountered some skepticism — he was questioned at a meeting with Iowa pastors last month about his campaign’s reliance on money from New York financier Paul Singer, a major GOP donor who supports causes including same-sex marriage.

Trump performs well in national polls among self-described evangelical voters, but many top activists and group leaders consider the real estate magnate insufficiently committed to opposing abortion and same-sex marriage.

Other evangelical favorites, such as retired neurosurgeon Ben Carson, former Arkansas governor Mike Huckabee and former senator Rick Santorum (Pa.), remain beloved but are considered unable to defeat Trump.

In Iowa, where social conservatives are expected to hold sway Feb. 1 in the first-in-the-nation caucuses, Cruz has another scheduling advantage. A few days before the voting, he will be the sole candidate to appear before more than 100 Iowa clerics attending a pastors event in Des Moines.

“Ted Cruz made a significant investment in a ground game that looks to pastors to register and mobilize the pews,” said David Lane, an activist who is organizing the January meeting in Iowa and arranged for several GOP contenders to meet previously with clergy members. “Neither Trump nor Carson nor Rubio have done that.”

Polls have shown Cruz surging in Iowa as a result, in part, of his rising support among evangelicals. A Monmouth University survey in Iowa showed him winning 30 percent of those voters, compared with 18 percent for Trump and 16 percent for Rubio.

A significant moment in the battle for evangelical support came during the Dec. 7 meeting of evangelical leaders that preceded the string of endorsements. Huddling in a hotel in suburban Washington, the group held an extended debate about whether to support Cruz or Rubio and in the end voted for the Texan, participants said.

Participants said the effort was organized in part by Tony Perkins, president of the Family Research Council, who has long urged Christian conservatives to pick a consensus presidential candidate early in the nomination process. The idea of an early endorsement has been discussed for several recent election cycles, but pressure has increased this time following frustration among Christian conservatives with the nominations of Sen. John McCain (Ariz.) in 2008 and former Massachusetts governor Mitt Romney in 2012.

Perkins, who has not publicly endorsed a candidate, declined to discuss the matter, as did several others who attended. The meeting was first reported by the National Review.

About 50 conservative leaders had met periodically since 2014, referring to themselves simply as “the Group.” Early on, participants settled on three criteria for backing a candidate: electability, reliability in support of positions important to social conservatives, and having the financial and organizational capability to be competitive in as many as 30 states.

Dobson, one of the most influential social-conservative voices nationally, last week issued a statement distributed by the Cruz campaign saying he had met with the candidate multiple times. Dobson said that he and his wife, Shirley, had “been praying for a leader such as this” and that they asked “conservatives and people of faith to join us in supporting his race for the presidency.”

Dobson is expected to join 100 other faith leaders at the meeting on Dec. 28 and 29 at the ranch in tiny Cisco, Tex., where Cruz and the other guests are expected to discuss campaign strategy, policy ideas and religious philosophy. The meeting will include clerics from some of the country’s largest churches, including African American and Hispanic congregations that make up an increasingly large share of the evangelical movement.

Among those invited to attend are Bishop Harry Jackson, the conservative black pastor of the 3,000-member Hope Christian Church in Beltsville, Md., and Samuel Rodriguez, a California-based pastor who leads the National Hispanic Christian Leadership Conference. Jackson declined to discuss his involvement with the broader coalition of evangelical leaders. He confirmed his plans to attend the Cisco gathering, although he has not committed to any candidate.

In an interview last week, Rod­riguez said he was not sold on backing Cruz, whom he said he knows and admires. He said that the senator was doing well among white evangelicals but that his recent tough talk on immigration, in which he voiced strong opposition to a path to citizenship for millions of undocumented immigrants, “carries the potential to alienate Latino voters.”

Rodriguez said many Latino evangelicals appear to be leaning toward Rubio, who, like Cruz, is Cuban American but who has said he supports an eventual legalization for undocumented immigrants.

Mike Gonzalez, the executive director of the South Carolina Pastors Alliance and another Hispanic pastor planning to attend the meeting in Texas, has a different view. Cruz will connect with Latino voters, Gonzalez said, noting that many share the senator’s position on enforcing immigration rules.

“I believe in the rule of law, as does Ted Cruz,” Gonzalez said.

Gonzalez said he plans to bring five South Carolina pastors to the event with him, two of whom have endorsed Cruz.

“I hope we’ll have additional endorsements by the time we leave,” he said.

The gathering in Texas will include a private fundraiser attended by brothers Farris and Dan Wilks, who have underwritten one of three super PACs backing Cruz. The Wilkses have funded conservative causes using the fortune they made from several energy and real estate companies they founded in Cisco, population 3,800.

Although much of the two-day gathering will be private, it will end with a public rally that will include a speech by Cruz and music by the Newsboys, a popular Christian rock band.

David Barton, an organizer of the event who leads one of the super PACs backing Cruz, said he would not be surprised if more than 1,000 people attend the rally and concert, in addition to those who will be at the invitation-only meeting at the Wilkses’ ranch.

“We were blown away by the RSVPs,” said Barton, a former vice chairman of the Texas Republican Party who has written books about the Christian heritage of the United States and encourages church leaders to engage in politics.

Cruz’s January meeting with Iowa pastors will be the final pre-caucus gathering of the state’s Pastors and Pews organization. The effort is part of the American Renewal Project, which seeks to be an “honest broker” for the faith community in evaluating candidates, said Lane, the group’s founder.

Rubio received an enthusiastic response when he met with the Iowa pastors group Nov. 24 and answered questions about his faith and his connections to Singer, the donor known for his support of same-sex marriage.

“When someone cooperates with my campaign, they are buying into my agenda. I am not buying into their agenda,” Rubio said, according to a video recording by the Christian Broadcasting Network. The candidate said he is allied with Singer on national security issues and support for Israel but has never discussed marriage.

His answers drew an enthusiastic reaction, and Lane said the group was impressed by his comments on faith. But Lane questioned why Rubio “waited until 60 days before the caucuses” to reach out to Iowa pastors. Cruz, he said, has been working with the organization for more than a year.

Katie Zezima contributed to this report.

Correction: A earlier version of this article incorrectly rendered the name of the South Carolina Pastors Alliance.