The crux of Ted Cruz's campaign has long been mobilizing the Christian right to his side, working to galvanize enough evangelical voters to topple Donald Trump.

The Texas senator even launched his campaign at Liberty University, which claims to be the world's largest Christian college, declaring that "God isn't done with America yet."

Cruz talks with the cadence of a megachurch pastor, and exhortations of his faith are a mainstay at every campaign rally. His strategy in targeting the most conservative religious voters worked in Iowa, but the wheels came off in South Carolina and Nevada.

Now, if he can't fully convert religious voters in many critical Southern states set to vote on Super Tuesday, his campaign could be beyond resurrection.

"I think for him to continue to lose evangelical votes to Donald Trump is a fatal blow to the rationale for his campaign," said Bruce Haynes, a GOP strategist and president of the bipartisan consulting firm Purple Strategies. "He speaks openly of the relevance of his candidacy in churches and has openly identified that a key part of their winning strategy is evangelical voters. That's his base, but he's not carrying that base."

Cruz Battling Trump And Rubio For Evangelical Voters

The so-called SEC primary runs through states that are likely to have even more evangelical voters than the states that have voted so far. Cruz himself has only raised expectations about Super Tuesday, calling it "the most important day in this entire cycle."

According to 2012 exit polls, in Alabama 80 percent of GOP primary voters described themselves as evangelical. In Tennessee, 68 percent of Republican voters were born-again Christians. And in Georgia, 68 percent of primary voters four years ago were evangelicals.

Those states could have higher evangelical turnout than states that have already voted this year, according to 2016 exit poll data. In Iowa, 64 percent of GOP caucusgoers were evangelical, while in South Carolina 72 percent described themselves as born-again. Those numbers were up from four years ago. Super Tuesday states could see a record number of voters, including more evangelical voters, go to the polls.

With a heavy ground game, Cruz won 34 percent of evangelical voters in the Hawkeye State; Trump got 22 percent, while Florida Sen. Marco Rubio captured 21 percent. In South Carolina, though, Cruz finished third behind Rubio and lost the evangelical vote to Trump by 6 points, 33 percent to 27 percent. Rubio again got almost a fourth of that voting bloc though.

Now, just hours away from Super Tuesday, polls show Cruz's grasp on evangelical voters slipping away from him even more. And it's complicated by a rising Rubio, who is now getting nearly as much of the evangelical vote as Cruz is in some places.

"Cruz is basically splitting the evangelical vote with Trump, and Rubio's getting a share of that too," said Alan Abramowitz, a professor of political science at Emory University in Atlanta.

NBC News/Wall Street Journal/Marist polls released Sunday showed Trump easily beating Cruz in Tennessee and in Georgia. In Tennessee, that's fueled by a 15-point edge for Trump among white evangelicals and, in the Peach State, the bombastic billionaire is winning those voters by 8 points. Cruz does have a lead over Trump in his home state of Texas in those same surveys and wins evangelical voters there by 23 points.

The biggest loss for Cruz could come in Alabama, a state where 80 percent of GOP primary voters four years ago identified as evangelical. A Monmouth University poll released Monday showed Trump winning 42 percent of voters, while it was Rubio in second with 19 percent followed by Cruz with 16 percent. The split of evangelical voters in that survey follows the same trajectory — 43 percent for Trump, 18 percent for Rubio and 15 percent for Cruz.

The Texas senator got another blow on Sunday when Alabama's senior senator, Jeff Sessions, endorsed Trump over him. Cruz has frequently invoked his work and relationship with Sessions on the trail, particularly on immigration. But the hard-line conservative chose to throw his support behind Trump, and not his fellow senator.

Cruz's Trust Issue

But Cruz's plan to woo evangelical voters hasn't gone as planned. He is not just losing the critical voting bloc to a thrice-married casino mogul who until a few years ago supported the abortion procedure known as intact dilation and extraction and has even defended Planned Parenthood this year — he has also seen his own reputation take a hit as rumors of dirty tricks have plagued his campaign.

First, it was his staffers telling voters that neurosurgeon Ben Carson was set to drop out on Iowa caucus night, fueled by a CNN report saying his GOP rival was heading home to Florida after the vote. There have been misleading mailers and ads in South Carolina that the campaign has taken heat for; a superPAC supporting him even had to take down a misleading TV spot that hit Rubio. And some voters in the Palmetto State said the label of "liar" that his opponents were trying to paint him with was sticking.

"If Cruz doesn't win any of these contests outside of Texas, I think that's a really big sign for his campaign," Abramowitz said. "The lying charges have clearly hurt him, and also the fact that he has no support from any of his colleagues in the Senate is hurting him."

Cultural Vs. Committed Evangelicals

Even if Cruz does lose born-again voters on Super Tuesday, that doesn't mean Trump has somehow converted even the most faithful to his side. Top leaders in evangelical churches have denounced his rhetoric banning Muslims from coming into the U.S. and his refusal to say he has ever asked God for forgiveness. Still, he has received the support of Liberty University President Jerry Falwell Jr., and Robert Jeffress, pastor at First Baptist Dallas, has introduced Trump at many rallies and spoken very highly of him, though he hasn't officially endorsed.

It's important to remember that the seeming wide swath of evangelical voters who will go to the polls is not homogeneous, either in political or in religious beliefs. And defining what exactly constitutes an evangelical voter can be misleading in polling. A Vox study this month noted that "regular, weekly church attendance — as measured by a standard Pew Research question included in my survey — predicted a statistically significant and substantive opposition to Trump."

That's an important distinction, especially in the South, where church and religious activities are ingrained in the culture, but degrees of devotion vary.

"In the South, there aren't that many people willing to answer the phone and tell a live human being they're not born-again. After all someone in the room might be listening," said Haynes.

"The culture of the South is replete with people who've answered an altar call and qualify as born-again, but 20 years later it would be difficult for them to demonstrate how they're living an evangelical, Christ-centered life," he continued. "They're Christian by definition, but it's not the central driving force of their life."

It's those, maybe more tepid believers whom Trump has tailored an appeal to, with his bombast against illegal immigrants, America's weakness abroad and promise to restore the country's greatness. And in the South, it's that type of voter who will dominate the contests on Tuesday, likely denying Cruz his last prayer of a campaign resurgence.

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