Washington (CNN) With 15 official Republican presidential candidates, evangelicals have something they haven't had as much of in previous cycles: choices.

And lots of them.

But while evangelical voters and leaders see opportunity in the bumper crop of 2016 GOP candidates, they also see peril.

"It's the tale of two cities, good news and bad news. The good news is that we have a lot of good candidates, but the bad news is that it's also a recipe for division," said Bob Vander Plaats, the Iowa-based CEO of The Family Leader, a Christian conservative group. "It would be great if we could unite behind one candidate, but historically, that's been easier said than done."

Vander Plaats' group will host at least nine of the candidates in the Hawkeye state on Saturday, proof that the majority of the Republican candidates are courting the evangelical vote.

Christian conservative voters could make up as much as 40% of the Republican primary electorate in 2016 -- even more in some states, particularly in the South. As they sort through the candidates, many of whose fates will rise and fall on this constituency's vote, evangelicals are likely to heavily weigh not only their policy positions but also their biographies and how well they speak the language of faith.

"Everybody has to do the checklist on social issues -- pro-life, gay marriage -- that's a threshold they all have to meet," said David Yepsen of Southern Illinois University, who has covered nine Iowa caucuses with the Des Moines Register. "But evangelicals are looking at moral character issues. They are looking for a sense of who they are. Are they a person of faith? Is this a godly person? All subjective questions."

Those were the kind of questions that helped evangelicals coalesce around former Arkansas Gov. Mike Huckabee in 2008 and former Pennsylvania Sen. Rick Santorum in 2012, both of whom have entered this year's race and are competing to re-establish their former coalitions.

But some evangelicals say those considerations aren't sufficient to win their votes; the candidate's ability to implement their vision is also key.

A candidate with values and executive skill

"In the past, candidates could quote from hymn books and talk about personal faith in a way that evangelicals would respond to. I don't think that's going to work anymore," said Russell Moore, president of the Ethics and Religious Liberty Commission of the Southern Baptist Convention. "They are looking for a candidate who understands religious liberty and who can lead a massive bureaucracy."

Though nearly every Republican candidate embraces stances important to evangelicals -- opposition to same-sex marriage and abortion, strong support for Israel and religious liberty -- differences in their approaches on these issues are already emerging.

After the Supreme Court's decision legalizing same-sex marriage, several candidates, including Huckabee and Louisiana Gov. Bobby Jindal, both evangelicals themselves, forcefully challenged the decision, criticizing the composition of the court and promising to fight the outcome in various ways.

Wisconsin Gov. Scott Walker, another evangelical candidate, floated the idea of a constitutional amendment that would grant states the right to define marriage.

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Others, such as former Florida Gov. Jeb Bush and South Carolina Sen. Lindsey Graham, said they would respect the decision -- and supporters of same-sex marriage -- and suggested the new focus should be on religious liberty rather than trying to overturn settled law.

What will ultimately play with evangelical voters in early primary states like Iowa and South Carolina remains an open question as candidates line up on various sides of the marriage debate.

"Evangelical voters are looking for a thoughtful leader at a time like this, not someone who is simply an agitator," said Craig Robinson, a conservative Iowa blogger.

"It's the next battle, the preservation of the free exercise clause contained in the First Amendment, that they need to be concerned with," he continued. "Do churches in America really have the freedom to practice and teach their faith or are they also required to succumb to the opinions of the U.S. Supreme Court?"

In the wake of the court's marriage decision, religious liberty is a rallying point that many Republican candidates have rushed to embrace, as it has seemed to many like a more viable path given the growing public support for same-sex couples.

It is also one that conservative candidates are widely able to embrace.

An emphasis on religious liberty

Kentucky Sen. Rand Paul, a favorite with the libertarian wing of the Republican Party that has at times embraced an agenda clashing with that of evangelicals, sees religious liberty as a message that works for both constituencies. He's focusing on liberty and freedom as a God-given right, framing the Charleston, South Carolina, church shooting, for instance, as a crisis of faith.

Still, it can be easier for a candidate like Huckabee -- a former pastor -- to connect with evangelical audiences. Huckabee is hewing closely to the straight-faith-talk script that helped him in 2008. Among his targets: the Supreme Court and "coastal elites" who live in the "bubble-ville" as opposed to "Bubba-ville."

Another of his targets is Beyonce. He criticized the pop star and her husband, Jay-Z, for their sexually suggestive lyrics and stage performances.

Rookie presidential candidates like Texas Sen. Ted Cruz and retired neurosurgeon Ben Carson, who has been in the top tier of candidates in some past national polls, also see a path that runs through the pews.

Carson, a Seventh Day Adventist, often tells the story of how he grew up angry and how he prayed to God to help him control his temper after he tried to stab a friend who had changed the radio station.

Cruz, whose father is an evangelical minister, announced his candidacy at Liberty University, which describes itself as the largest Christian university in the world. In his address, Cruz told the story of his father deciding to stay with his family after attending a Bible study in Houston.

"There are people who wonder if faith is real. I can tell you, in my family, there's not a second of doubt," he said. "Because were it not for the transformative love of Jesus Christ ... I would have been raised by a single mom without my father in the household."

Similarly, Jindal, a converted Catholic, led with his faith in his announcement speech.

"There's a big country out here with millions of Americans who believe in God and are not ashamed to say so," Jindal said. "I would be wary of a president who didn't seek wisdom from the Almighty."

While Bush has been more muted on same-sex marriage and other key issues for evangelicals, he's looking to make inroads where he can. He drew some of the biggest cheers during his announcement speech with a line about the Little Sisters of the Poor lawsuit against the federal government objecting to the Affordable Care Act's contraception coverage mandate.

"It comes down to a choice between the Little Sisters and Big Brother, and I'm going with the Sisters," Bush said.

He has also pointed to his defense of Terri Schiavo, a Florida woman in a persistent vegetative state while he was governor whose husband waged a successful legal battle to take her off life support.

An open field

The jumble of candidates means there are a lot of undecideds, though some early favorites are emerging. The silver-tongued Cruz, for instance, has connected with evangelical audiences like few other candidates with his televangelist-like stage swagger.

But still, it's early.

"I'd be pleased with most of them, but my favorite is Ted Cruz," said Rebekah Tabb, 21, who attended the recent Faith and Freedom Forum in Washington, where declared and presumptive GOP candidates courted evangelicals.

"They all have potential. Ben Carson, he's a good guy, too. And I really like Jeb Bush and Chris Christie," she said, but added, "I noticed that some are not that vocal on traditional marriage and that makes me nervous."

John Radall, 69, who is in the leadership of the Faith and Freedom Coalition in Delaware, has settled on Cruz.

"For me, it's easy. I'm looking for change and Sen. Cruz has fought for change," Radall said. "And he does it with a moral and ethical heart."

A recent CNN/ORC Poll shows Huckabee in first place among white evangelicals, with Walker, the son of a pastor, a close second.

Huckabee won Iowa in 2008 and has been among the most strident in his opposition to same-sex marriage. And Walker got off to a fast start in neighboring Iowa by framing himself as the kind of conservative who can win and govern.

At a recent gathering of Hispanic evangelicals, Huckabee tried to press an advantage he feels he has with the constituency over Bush, a Spanish-speaking Catholic with a Mexican-born wife.

"I do not come to you tonight with the ability to speak Spanish," Huckabee said. "But I do speak a common language: I speak Jesus."

The choices are exciting to some evangelicals, who often felt frustrated with the eventual 2012 GOP nominee, Mitt Romney.

"The diversity of candidates is good for the process," said Warren Smith, associate publisher of World Magazine, a Christian outlet. "It's causing everyone to sharpen their message."

But there are also risks in having so many options. Namely, that evangelicals will split their vote and clear the path for a candidate less sympathetic to their views.

Lynn Proudfoot, a 63-year old Iowa resident who backed Tom Tancredo in 2008 and Michele Bachmann in 2012, is mindful of that threat.

He is determined to help his fellow Christian conservatives find a consensus choice "to prevent another Bob Dole situation."

But first, he has to settle on a candidate.

"Right now I'd put Ted Cruz in the top spot, but it's close because I like Bobby Jindal, too," Proudfoot said. "I haven't made a final decision and I'm open."