If he were running for president today, Thomas Jefferson would not be elected. Strip away glaring anachronisms like slaveholding, along with his poor public speaking skills, and Jefferson would still struggle in the polls. The reason would be obvious to the current field of candidates: Jefferson was an ardent critic of organized religion, says Bruce J. Schulman, William E. Huntington Professor of History.

Jefferson’s unusual religious views—he didn’t believe in the divinity of Jesus, and he advocated a strong separation of church and state—were a point of contention in the election of 1800, when the opposition “basically said any Christian has to vote against this essential atheist,” says Schulman. But he was elected anyway, and is now revered as a founding father.

More than two centuries later, presidential candidates must publicly embrace a strong faith if they want to win. An incident in the 2016 race shows how times have changed. In May 2015, Hillary Clinton, a lifelong Methodist, walked into a South Carolina bakery while on the campaign trail and struck up a conversation with a customer about the passage he was reading in his Bible. Their talk gained Clinton his support. The former secretary of state’s Bible knowledge “is important in my world,” the man, a Baptist minister, later explained to CNN. “I’d like to know that my president has some religious beliefs in God.”

Clinton may not trumpet her faith on the stump as much as some candidates do, but she knows how to use it to connect with people.

Today, says Schulman, “it’s almost impossible to win the presidency without some show of serious religious commitment.”

How did we transform from a nation that could look past Jefferson’s criticisms of religion and elect him president to one that wouldn’t tolerate them? Religion, which has long been an “indispensable part of American public life,” is “perhaps more central to American politics than ever before,” Schulman and his coeditors write in Faithful Republic: Religion and Politics in Modern America (University of Pennsylvania Press, 2015). The book offers new or rarely explored insights into the relationship between religion and politics from the early 20th century to the present—from church and state responses to the New Deal to the rise of the Religious Right in the 1970s. It also points out that while America is becoming increasingly secular—“Recent polling shows that the fastest growing religious groups are nonbelievers and those who identify as ‘spiritual but not religious,’” the editors write—religion is taking anything but a backseat in presidential elections.

“In 2012, unease about Mitt Romney’s Mormonism persisted among liberals and conservatives alike,” the editors write, and “in 2008, controversial liberation theology sermons by Reverend Jeremiah Wright threatened to undermine Barack Obama’s candidacy (while a small minority of Americans doubted whether Obama was even a Christian).”

Faithful Republic is one example of how historians are paying greater attention to religion’s crucial role in shaping US history and politics. Another is Religion in Early America, the Smithsonian’s forthcoming exhibition—its first ever on the topic. The exhibition, for which Professor of Religion Stephen Prothero served as advisor, will feature documents, images, and objects such as George Washington’s christening robe and Bibles owned by Presidents Jefferson and John Quincy Adams.

Exploring religion’s shifting influence helps explain the current US political landscape, from why presidential candidates talk so much about God to why the parties clash over American exceptionalism, and gives a glimpse of what the country might expect in the 2016 elections.

Praying for Votes

When Jefferson was running for president, elections were very different from what they are today. Voting was heavily restricted (largely to wealthy white males) and political parties were not as established as they are now. “You don’t have candidates going around the country making speeches,” says Schulman, “so personal statements of faith are really not a part of political campaigns.”

One issue that nudged candidates’ personal faith further into the electoral limelight was immigration. As waves of Catholics began arriving from Europe in the early 1800s, religious tensions boiled. Protestants believed Catholics’ loyalty to the pope above other authorities made them unfit citizens. That suspicion lessened over time and with restrictions on mass immigration, says Schulman, but it was still potent enough to force John F. Kennedy (Hon.’55) to openly address his Catholicism in a speech in 1960 to reassure a nervous public. Accused of being unpatriotic and a Catholic Communist, Kennedy downplayed his faith, assuring his audience of Protestant ministers that he believed “in an America where the separation of church and state is absolute.”

But candidates didn’t really begin talking about their personal faith to win office until after the 1970s, says Schulman. Opposition to the secularism of the ’60s, to abortion, and to measures that established a clearer separation between church and state, such as the banning of school-sponsored prayer, galvanized the Religious Right. Evangelicals would boost the campaigns of Republicans like Ronald Reagan, George H. W. Bush (Hon.’89), and George W. Bush. Now, “the role of evangelical Protestants is so strong,” says Schulman, that it shapes “the entire presidential selection process.”

Today, most Americans want a president of faith. In a 2014 Pew Research Center survey, 53 percent of Americans said they would be less likely to support a presidential candidate who does not believe in God. As recent elections have shown, they also expect presidential candidates to talk about their personal faith.

“The rise of the Religious Right has changed the landscape so that” in most of the United States overt religious expression is an expected part of our politics, says Schulman, “and overt irreligion or non-religion is something that’s become more or less unacceptable.”

PLAYING THE FAITH CARD

As they’ve watched religion help Republicans win the White House, Democrats have tried—with varying levels of success—to convince Americans they have the spiritual chops worthy of the Oval Office.

“It was a pretty widespread perception that one reason John Kerry lost in 2004 was because he just couldn’t convey any sort of faith to the American people,” says Prothero. “He sort of seemed like a secularist, and people didn’t like that. [It wasn’t so much] that he was Catholic—it just seemed like he didn’t have any piety. Democrats now have learned from that, and they talk about religion a lot.” He notes that the strategy of “Hillary Clinton and Obama has been to co-opt efforts by Republicans to claim the Christian mantle for themselves and [their efforts] to claim that there’s only one kind of Christianity.”

We can expect candidates to continue to play the faith card in 2016. Clinton will “talk more about [religion] as the election moves on,” he speculates.

If the Democratic Party’s challenge is knowing when to talk about faith, the Republican Party’s is knowing when to stop talking about it. A lineup including Mike Huckabee (an ordained Southern Baptist minister) and Ted Cruz and Ben Carson (both sons of ministers) guarantees strong testimonies of faith and plenty of references to God and morality. But candidates like these have to be careful: talking too much about religion and morals could cost them the Oval Office. Prothero, whose new book Why Liberals Win the Culture Wars (Even When They Lose Elections) is due out in January 2016 from HarperOne, says he’s joked that the Republican primaries could be the best thing for the Democratic Party.

“Culture war politics is very successful on the right for state and local elections, but it’s not successful at the national level,” he says.

Voicing opposition to issues such as abortion and gay marriage in the primaries might fire up some GOP members, but can make hopefuls “look like fringe candidates” to others—never mind voters beyond the confines of the party, says Prothero. Faithful Republic cites Republican Rick Santorum’s failed 2012 presidential bid as an example: the Catholic gained favor by opposing abortion and gay marriage, but not when he spoke out against contraception; he lost the nomination to Romney.

Prothero expects 2016 won’t be much different, because, he says, “in order to win the Republican nomination you have to appeal to cultural conservatives.”

UGLY POLITICS

The boost that the culture war gave right-leaning politicians after the 1970s contributed to the partisan politicking we see today, says Schulman. As he wrote in Rightward Bound: Making America Conservative in the 1970s (Harvard University Press, 2008), the “stern individualistic morality and apocalyptic, black-and-white worldview” of right-wing evangelicals like Jerry Falwell “proved more appealing than the nuanced perspective of evangelicals who focused on social-justice issues and on the ambiguities and pitfalls of partisan politics.” Over time, both parties politicized more issues, from history and education to the environment and foreign policy. Today, says Prothero, “we play out these culture wars not just in terms of abortion and in terms of same-sex marriage, but in all these fields.”

One squabble we can expect to see in the 2016 election concerns American exceptionalism—the idea that the US has a unique role to play in history and in the world. Exceptionalism rears its head in debates on almost everything from economic to foreign policy. Prothero says these clashes “can be read pretty straightforwardly almost as theological debates about how covenantal theology works”—is God our critic or our backslapper?

Christians of both parties believe in the idea of America as a special, “promised land,” an idea dating back as early as the settlements of the Pilgrims and the Puritans. But they sometimes part ways on what it means to be a chosen people—and on the rhetoric for talking about it. Republicans, says Prothero, emphasize pride in the US as the greatest country in the world, wanting to see the US demonstrate “moral superiority”—one reason negotiating with Iran over its nuclear capabilities was such a point of contention. Democrats, however, commonly speak in a prophetic mode about how the nation needs to do better at living up to its ideals of equality, justice, and so forth.

TOGETHER, FOR BETTER OR WORSE

In the end, the politicization of religion could come back to haunt politicians—and church leaders. In fact, surveys of young people show this to be a contributing factor in the rise of the religiously unaffiliated, says Prothero. These so-called “nones,” expected to grow to roughly a quarter of the population in 2050, don’t want to be associated with a party—or politicians—they may not agree with. “I think the vitality of American religion has really been hurt by the recent push toward more and more religion in the political space,” he says. “And there are some evangelicals saying, ‘You know, we made a mistake. We need to get out of this political game, because our brand is being hurt.’”

But the entanglement of religion and politics can be used for good, as it was in the abolition and civil rights movements. And while voters in more secular countries are befuddled by the idea of voting for a candidate who waxes on about Jesus, the phenomenon is in some ways a reflection of our nation’s history of religious freedom. Since the US “didn’t have a state church, religion was actually able to thrive more here,” says Prothero. Religion was freed, he explains, from the official political ties that damaged it in times of upheaval, like the French Revolution.

For good or ill, the ongoing importance of religion in US elections also shows that Americans still have a soft spot for faith—even if they’re less likely to be found in the pews. In 2013, more than half of Americans said religion was “very important” in their lives and that it “can answer all or most of today’s problems.”

Historians are getting the message. Whether through new scholarship or exhibitions like the Smithsonian’s, they’re working to integrate religion more deeply into their understanding of the country’s past—and present. “I think part of the reason that there’s been a new interest among scholars in the role of religion is the obvious question of trying to explain the world that we live in now,” says Schulman. He and Prothero point out that religion is critical to understanding a wide range of recent events, from 9/11 to the success of Walmart, a company informed by the religious views of the Walton family.

“Events have sort of overtaken the secular bias among historians,” says Prothero. It’s becoming more difficult, he says, to ignore “that religion matters in American History.”