Former vice president and current Democratic presidential candidate Joe Biden meets with clergy in June. (Jim Watson/AFP/Getty Images)

On Ash Wednesday, which begins the Christian season of Lent, presidential candidate Joe Biden participated in a CNN town hall. Remnants of ashes—a public declaration of penitent faith—could be seen on Biden’s forehead as he spoke to a minister whose wife was murdered in the Charleston church shooting. “I happen to be a practicing Catholic,” Biden said, visibly moved. He quoted a phrase from the theologian Søren Kierkegaard that gives him hope in times of grief: “Faith sees best in the dark.” The quotation became particularly comforting after his son Beau died, he told Stephen Colbert in 2015. And it’s a quote that the former vice president has repeated many times on the campaign trail.

Joe Biden has put his Catholic faith on display throughout his public life. He regularly attends Mass, wears a rosary, and speaks openly about the meaning, values, and purpose he derives from Catholicism. If elected, Biden would be only the second Catholic president in history. However, his personal appeal to fellow Catholics does not mean he has a lock on their votes. President Trump’s campaign is also pursuing Catholic supporters, and his most recent Supreme Court pick Amy Coney Barrett, confirmed just days before the election, holds a strong appeal for conservative Catholics. Moreover, Catholic voters, like all voters with religious persuasions, are not a monolith. “Catholics are multi-issue voters,” Josh Dickson, the Biden campaign’s national faith engagement director, told me. “And we are fighting for every single Catholic vote.”

Catholics have long been considered important swing voters, especially in battleground states. They make up one-fifth of the U.S. population (down from a quarter in the early aughts), and polls show that overall they are evenly split between the parties. Catholics of color make up an increasing share of the U.S. church, which is now 59 percent white and 34 percent Hispanic, according to Pew. Exit polling from 2016 showed that Donald Trump won 50 percent of the Catholic vote to Hillary Clinton’s 46 percent, with roughly 59 percent of white Catholics voting Republican and 74 percent of Hispanic Catholics voting Democratic. Those leanings have shifted over the past four years: An October 15 Pew survey found that Catholic voters prefer Biden to Trump, 51 to 44 percent. Sixty-seven percent of Hispanic Catholics support Biden, while Trump’s former 19-point lead among white Catholics has dropped precipitously to just 8 points (51 to 43 percent).

Catholic voters could determine who will be the next president, especially if Biden continues to undercut their support of Trump. The former vice president is currently leading in the swing states of Pennsylvania, Michigan, and Wisconsin, all home to large shares of white Catholics. In the battleground states of Florida and Arizona, which are home to many Hispanic Catholics, Biden narrowly leads and ties with Trump, respectively. Understanding how Catholic voters, particularly on-the-fence white Catholics, might influence the outcome of this election necessitates understanding their historical status as a swing vote—and how this sliver of a demographic could turn the fate of an entire country.

“White Catholics have been a swing vote in America, but they’ve been turning to the right for the last three election cycles,” said Ryan P. Burge, an assistant professor of political science at Eastern Illinois University. “And then, over the last four years, they shifted back to the left.” In a recent article for Christianity Today, Burge outlined the slipping support for Trump among white Catholics. In April of 2020, white Catholics preferred Trump by 56 percent, but by September, Biden and Trump were locked in “a statistical dead heat,” with white Catholic support for Biden jumping by almost 8 percentage points. The white Catholic vote may be a 50-50 split this year—“a huge shift from the 18-point margin Trump won in 2016,” Burge told me. Should that happen, the chance that Trump is able to make up the difference with other voters is slim: “He’s losing by subtraction,” Burge said.

True swing voters are coveted but increasingly rare: An August Wall Street Journal/NBC News poll found that just 10 percent of registered voters plan to vote for a different political party than the one they supported during the 2016 presidential election. Still, both campaigns are treating Catholic voters as if they are crucial to electoral victory. The Trump campaign has received support from Catholic surrogates, including former House Speaker Newt Gingrich (whose wife Callista is the current ambassador to the Vatican) and Trump appointee Mick Mulvaney; both serve on the advisory board of Catholics for Trump. The president of the anti-abortion group Susan B. Anthony List, Marjorie Dannenfelser, is Catholic and also leads “Pro-Life Voices for Trump.” Groups like CatholicVote, a non-profit with a connected PAC of the same name, are bolstering Trump’s reelection effort as well. This conservative PAC recently launched a $9.7 million ad campaign targeting Catholic voters in swing states with anti-abortion messages. The Trump campaign seems to be exercising a similar strategy with white Catholic voters as it has, very successfully, with white evangelicals: focusing on the issue of abortion and pressing forward with the nominations of Supreme Court justices sympathetic to conservative goals.

Such a strategy rests on the expectation that these issues are priorities for Catholic voters. However, the available data paints a more nuanced picture. A recent poll conducted by RealClear Opinion and the Eternal Word Television Network (EWTN), a Catholic news organization that leans conservative, asked Catholics who are likely voters to identify the issues that matter most to them. The top three issues were the economy and jobs (91 percent), healthcare (89 percent), and the coronavirus pandemic (88 percent). The Supreme Court came in 11th place at 68 percent, and abortion ranked last of those issues listed, coming in at 13th place, with 59 percent saying it was a top priority. Biden has faced criticism from Catholics and conservatives for supporting abortion rights, which contradicts Catholic teaching. Notably, the former vice president was denied communion at a Catholic church in South Carolina last year over his support for abortion rights. But a slim majority of the U.S. Catholic laity seems to align with his views: 56 percent of U.S. Catholics support legal abortion, according to Pew.

The Biden campaign has been conducting a broad outreach to Catholic voters. They have launched multiple coalitions dedicated to reaching religious voters through phone banking, voter turnout initiatives, and virtual roundtable discussions, among other events. One of these coalitions, Catholics for Biden, is co-chaired by prominent Catholic surrogates for the campaign like Sen. Tim Kaine and religious historian Anthea Butler. Joan Neal, a former executive vice president at Catholic Relief Services and a Catholics for Biden co-chair, told me the three dozen co-chairs have been “given a lot of freedom” to focus on the areas of outreach about which they are passionate. Neal’s efforts have primarily focused on reaching Black Catholics; she has created a voter guide for the Black Catholic community and developed a prayer for Black Catholics to pray leading up to the election “for God’s help and the inspiration of the Holy Spirit.” The campaign has also launched a series of ads highlighting Biden’s personal faith and touting the endorsements he has received from more 1,600 faith leaders. Spearheading many of these endeavors is Dickson, the campaign’s national faith engagement director and a former Republican evangelical whose Twitter bio identifies him as a “Common good Christian.”

The “common good” is a phrase that appears frequently in the Biden campaign’s messaging—Dickson himself recently described the campaign as being “deeply aligned with the common good values of Catholics.” It’s a nod to Catholic social teaching, which the U.S. Conference of Catholic Bishops describes as a “rich treasure of wisdom” instructing Catholics how to pursue the common good, which means “building a just society and living lives of holiness amidst the challenges of modern society.” John Carr, the director of the Initiative on Catholic Social Thought and Public Life at Georgetown University, told me that Biden speaks the language of the common good as he campaigns: “When Biden talks about dignity, when he talks about the least of these, when he talks about treating everyone with respect—these are the building blocks of the common good.”

Carr spent more than two decades working with the U.S. Conference of Catholic Bishops, shaping the documents used to guide Catholic political engagement. He has never publicly endorsed a presidential candidate until this election. In a recent statement explaining his endorsement of Biden, Carr described himself as “politically homeless” but conscience-bound to vote for a candidate who, broadly speaking, will “seek the common good.” Carr does not support what he calls Biden’s “abortion extremism,” but he also says his Catholicism calls him to consider a range of issues when voting. “Our faith puts at the very center of our lives what we do for the least of these, and I believe that begins with unborn children, but it certainly doesn’t end there,” Carr told me.

Neal expressed a similar sentiment to me, emphasizing a “consistent ethic of life” that “preserves and protects life not just from threats in the womb, but from a lack of access to all the things that support the thriving of life.” For Neal, this mandate includes not only access to healthcare and a quality education, but also police reform and opposition to the death penalty and mass incarceration. “We need to care for unborn lives, but we also need to care for them once they are born.”

The Biden campaign’s broad emphasis on the common good may be enough to sway some white Catholic voters who have, as Burge told me, been “pushed away” by Trump’s divisiveness. Whether it will draw enough of these swing votes leftward to turn the election for Biden is unclear. Maria Mazzenga, the curator of the American Catholic History Research Center at Catholic University, noted that Catholics are like the U.S. population more broadly: “They vote in the same proportion of conservative and liberal as other voters in the U.S.” Still, there are voters who may respond to rhetoric that echoes Catholic social teaching. Mazzenga said, “If Biden talks about the common good, he could appeal to a group of Catholic voters who haven’t been addressed like this in a long time.”

Will the Biden campaign’s strategy triumph in winning over this key sliver of Catholic voters? As this election cycle comes chaotically to an end, polling certainly indicates that Biden is surging among voters, and he may yet win some of the white Catholic swing voters that could be critical to electoral victory. What does seem certain is that Biden’s faith—and his impact on Catholic voters both now and in election cycles to come—will remain squarely in the spotlight.

Elena Trueba is a writer based in Washington, D.C. She holds a Master of Theological Studies with an emphasis in religion, ethics, and politics from Harvard Divinity School.