It’s one of the most intriguing sub-plots of the 2016 election: Why are evangelicals, who historically have supported immigration reform and a path to citizenship for deeply felt religious and moral reasons, gravitating towards the two candidates who are most hostile to policy changes that would accommodate and integrate undocumented immigrants into American life?

Cruz has been working behind the scenes to line up the support of influential evangelical leaders around the country, and it has been paying off: he has already rolled out some big endorsements, and many more are set to come. Meanwhile, Cruz and Donald Trump have been dominating among evangelical voters: the last two Quinnipiac polls have showed the two men scooping up around half of Republican-aligned white evangelicals, each with far more evangelical support than any other candidate.

This, despite the fact that some polls have also shown a majority of evangelicals want Congress to pass immigration reform and support a path to citizenship. Yet Trump (who favors mass deportations) and Cruz (who flatly opposes legalization and would end President Obama’s executive actions shielding DREAMers from deportation on Day One) are more at odds with that posture than the other GOP candidates.

How to explain the disconnect? The answer lies in the nuances of evangelical thinking on matters such as Islam and the decline of American values, according to Robert Jones, the CEO of the Public Religion Research Institute, who has been studying evangelical opinion for years.

First, it’s important to note that the trends among evangelicals right now are really important to how the GOP primaries might turn out. According to calculations by Sabato’s Crystal Ball, an overwhelming majority of the total delegates in the primaries on or before March 8th will come from states whose electorates may be at least 50 percent white evangelicals. And as Slate’s Josh Voorhees explains, there is a very real possibility that in this cycle evangelical leaders will unify behind one candidate — Cruz — in a manner that could prove decisive. While evangelical voters continue to split between Trump and Cruz, it seems plausible that if Trump fades, Cruz may prove well positioned to inherit his evangelical voters, perhaps even consolidating that vote.

The evangelical support for Trump and Cruz is a bit surprising, given that evangelical Christians have long pushed for immigration reform that legalizes the undocumented on the grounds that we should welcome the “biblical stranger” among us who is merely trying to find a better life, as evangelical writer Jim Wallis has put it. Wallis is a liberal, but religion writer Sarah Posner has pointed out that many evangelical leaders have advocated for reform on the basis of “biblical imperatives” that require us to “seek justice for immigrants.”

PRRI’s Robert Jones, however, tells me that other nuances in evangelical opinion may be overtaking those sentiments.

“Trump is painting a bigger picture — a kind of appeal to nostalgia and to a mythical golden age that he wants to bring back in America that is very appealing to evangelicals,” Jones says. He notes that one recent PRRI poll found that 72 percent of white evangelical Protestants think the American culture and way of life has “mostly changed for the worse” since the 1950s.

“Evangelicals strongly believe American culture has changed for the worse,” Jones says. “If you listen to evangelical rhetoric, there are so many throwback words — retake, restore, revive, repent.”

Meanwhile, Jones notes that another recent PRRI poll found that 55 percent of white evangelical Protestants thinks that “the growing number of newcomers from other countries” is a threat to “traditional American culture and values.”

Trump, of course, has explicitly linked his call for mass deportations and his overall Fortress America approach to the quest to “make America great again.” But this broad set of evangelical sentiments may be helping Cruz, too. That’s because the Texas Senator, more than any other non-Trump candidate, has cast himself as the scourge of Washington elites who don’t have the spine to stand up to the ongoing transformation of the country — into something no longer recognizably American — that the Obama era is supposedly bringing about.

“Cruz is tapping into the sense that the country has really gotten off track,” Jones says, describing Cruz’s message as a “pox on both parties who are in bed with big business and other powers that are above our heads and behind our backs.”

All the anti-Muslim demagoguery may also be playing a role here, Jones adds. Trump, of course, has also linked the imperative of restoring American greatness to ideas such as a Muslim registry and a temporary ban on non-citizen Muslims from entering the U.S. Cruz has disagreed with such ideas. But Cruz, more than any other non-Trump candidate, appears to be trying to profit off the sentiments that Trump has unleashed: Cruz has declined to explicitly condemn such Trumpian rhetoric and has floated a religious test of sorts for Muslim Syrian refugees. Cruz has also been way out front in demanding that we describe the terror threat as “Islamist.”

One of the aforementioned PRRI polls also found that 73 percent of white evangelical Protestants think the values of Islam are at odds with American values and the American way of life.

“There are very high concerns about Islam among evangelicals,” Jones says. “Before Trump, in the evangelical world we had Franklin Graham, who had for years been out with scores of negative comments about Islam and Muslims. When Trump and Cruz come along, this is a familiar trope — one evangelicals are predisposed to hearing.”