Doug Mastriano, a Republican state senator from Gettysburg, Pennsylvania, and parts of neighboring counties, was a little-known figure in state politics before the coronavirus pandemic. But, in the past year, he has led rallies against mask mandates and other public-health protocols, which he has characterized as “the governor’s autocratic control over our lives.” He has become a leader of the Stop the Steal campaign, and claims that he spoke to Donald Trump at least fifteen times between the 2020 election and the insurrection at the Capitol, on January 6th. He urged his followers to attend the rally at the Capitol that led to the riots, saying, “I’m really praying that God will pour His Spirit upon Washington, D.C., like we’ve never seen before.” Throughout this time, he has cast the fight against both lockdowns and Trump’s electoral loss as a religious battle against the forces of evil. He has come to embody a set of beliefs characterized as Christian nationalism, which center on the idea that God intended America to be a Christian nation, and which, when mingled with conspiracy theory and white nationalism, helped to fuel the insurrection. “Violence has always been a part of Christian nationalism,” Andrew Whitehead, a sociologist and co-author of “Taking America Back for God,” told me. “It’s just that the nature of the enemy has changed.”

Mastriano grew up mostly in New Jersey, in a military family, and attended Eastern College, a Christian university outside Philadelphia. After he graduated, in 1986, he joined the military, and, as a junior intelligence officer, was stationed at the border of West Germany and Czechoslovakia. Mastriano, like many conservative Christians, came to see the Cold War as a spiritual campaign, applying religious notions of good and evil to U.S. foreign policy. “Seeing awful things in the East, and atheistic, communistic, socialist regimes oppressing people” convinced him of the need for “protecting freedom, the free people of the West,” he told “Crosspoint,” a Christian podcast, in 2018. While deployed, Mastriano often carried a Bible under his arm. “It wasn’t for show,” he said.

In 1991, as the Cold War was winding down, Mastriano was deployed to Iraq to fight in the Gulf War. He believed that he was on the front lines of a new religious conflict, this time against radical Islam. Mastriano’s wife, Rebecca, knew little about his posting, which was classified, and gathered people to engage in what she called “spiritual warfare,” praying that he would prevail against evil on the battlefield. In late February of that year, Mastriano’s unit was about to face Saddam Hussein’s Republican Guard, when a sandstorm struck. “Thunder and lightning and rain and sand, and it blinds the Iraqis. We can miraculously see through this silicon and moisture in the air, and we start picking off the enemy,” he said, on the podcast. “Because of this, our small regiment, compared to the armored divisions we were facing, was able to break the back of the Iraqi line and therefore end the war rapidly.” Days later, a ceasefire was announced.

Mastriano believed that this was a miracle, and evidence that Rebecca’s spiritual warfare had tangible results. “I believe I was saved by God, who answered the prayers of Pennsylvanians, “ Mastriano wrote to me in an email. “Rebbie played a significant role in leading those prayer efforts as she had more than twenty churches praying specifically for my unit.” For the next three decades, he continued to serve in military intelligence in Iraq and Afghanistan, where he appears to have developed a dim view of Islam. In recent years, he has often spread Islamophobic memes online. In one, he spread a conspiracy theory that Ilhan Omar, the Democratic congresswoman from Minnesota, directed fellow-Muslims to throw a five-year-old over a balcony. In another, he shared a graphic that read “Islam wants to kill gay rights, Judaism, Christianity and pacifism.” In yet another, he encouraged the idea that the fire at the Notre-Dame cathedral, in Paris, was started by Muslims, captioning a photo of two dark-skinned men grinning, “Something wicked this way comes.” (Mastriano did not respond to a request for comment on these social-media posts.)

In 2019, after retiring from the military and teaching at the U.S. Army War College, in Carlisle, Pennsylvania, Mastriano decided to run for office. “Our freedoms are being encroached,” he wrote to me, “and the precious lives of babies are eliminated without concern, while free speech is under attack by Orwellian-like ideologies that are taking over our public institutions.” Mastriano won a seat as a state representative in Pennsylvania. He soon began attending events held by a movement called the New Apostolic Reformation, a loosely linked network of charismatics and Pentecostals that, over the past decade, has played an influential role in conservative American circles. (Mastriano denied working directly with the group.) Many members believe that God speaks to them directly, and that they have been tasked with battling real-world demons who control global leaders. Prominent members in the group go by the title Apostle or Prophet to hark back to early Christianity. The N.A.R.’s overarching agenda—to return the United States to an idealized Christian past—is largely built upon the work of the pseudo-historian David Barton, who has advanced the idea that America was founded as a Christian nation. “Mastriano’s significance, alongside that of the N.A.R., is that he is attempting to create a theonomy—a system of enacting God’s law on earth,” Frederick Clarkson, a research analyst at Political Research Associates, told me. Bills that Mastriano supported in the legislature would have mandated teaching the Bible in public schools and would have made it legal for adoption agencies to discriminate against same-sex couples, among other things.

As lockdowns took hold, Mastriano railed against what he saw as the curtailment of God-given freedoms. “It says in John 8:36 that if Jesus set you free, you are free indeed,” he wrote to me. “This is why my motto is ‘Walk as Free People.’ ” On nightly Facebook fireside chats, he suggested that his viewers find new congregations if their pastors weren’t leading in-person worship services. He gained increasingly extreme followers; last June, at a gun-rights protest on the steps of the state capitol, he posed for pictures with white men in fatigues carrying AR-15s and several others in Hawaiian shirts, a hallmark of the Boogaloo Bois, a white-nationalist militia. In July, Mastriano attended a rally on the Gettysburg battlefield, where militia members gathered in response to a hoax circulated on social media that Antifa was going to topple Confederate statues. “A lot of people here just keeping an eye on stuff,” he said. “Americans doing American things. Isn’t that beautiful?”

Many white evangelicals reject the Christian-nationalist label. “Christian nationalism doesn’t exist,” Franklin Graham, the evangelical leader, told me, calling it “just another name to throw at Christians.” He added, “The left is very good at calling people names.” Mastriano also rejected the phrase, writing to me, “Is this a term you fabricated? What does it mean and where have I indicated that I am a Christian Nationalist?” But historians and sociologists have found the term useful to describe an undercurrent of nativist religion that runs through American history. “Christian nationalism was part of our cultural framework since the arrival of the colonists, who located what they were doing in the sacred, as part of God’s plan,” the author Andrew Whitehead said. John Winthrop, the seventeenth-century puritan leader, preached that Colonial America would become the “city on a hill” that Jesus described in his Sermon on the Mount. “In order to advance this Christian civilization, violence was required,” John Fea, a professor of history at Messiah College, told me. “Winthrop regularly talked about killing Indians in a providential way, and, two hundred years later, this language leads directly into Manifest Destiny.”

Throughout U.S. history, a combination of Christianity and patriotism often served as a rallying cry against a common enemy. Following the Second World War, many Christians came to believe, as Mastriano did, that the battle against communism was a religious struggle, in part as a result of the Soviet Union’s massacres of clergy members. President Dwight Eisenhower encouraged the pastor Billy Graham to stoke this fervor. Matthew Avery Sutton, a professor of history at Washington State University, told me, “From President Truman to Ronald Reagan, American Presidents allied with the Vatican and orthodox Christian leaders to frame the crusade against communism and atheism in hyper-religious terms.”

By the nineties and two-thousands, many white evangelicals had come to understand Islam to be the primary threat to America. “White evangelicals were already worried about the growth of Islam, especially beginning in the seventies with the Arab-Israeli war and the rise of oil,” Sutton told me. “What 9/11 shifts is that Muslims are no longer just a threat to Israel but a direct threat to the United States.” This hostility also turned on Muslim communities in America. At megachurches, pastors preached about the spread of “sharia law.” Secular liberalism and movements for social justice were also seen as threatening. “In the early two-thousands, among conservative pastors, you’d often hear that the gays are softening up our society in preparation for Islam,” Michelle Goldberg, the author of “Kingdom Coming: The Rise of Christian Nationalism,” told me.

The election of Donald Trump intensified certain strains of Christian nationalism. He fanned fears of pluralism with Islamophobic and anti-immigrant rhetoric. He often invoked Christianity, albeit in terms that were largely about ethnic identity rather than faith. “The greatest ethnic dog whistle the right has ever come up with is ‘Christian,’ because it means ‘people like us,’ it means white,” Samuel Perry, a sociologist at the University of Oklahoma and co-author of “Taking America Back For God,” told me. In 2019, Trump hosted Viktor Orbán, Hungary’s right-wing Prime Minister, at the White House, and praised him for building a border fence to keep immigrants out, saying, “You have been great with respect to Christian communities. You have really put a block up, and we appreciate that very much.”

Those who espouse Christian-nationalist ideas also appeared to grow more militant during this period. In the early years of Trump’s term, membership in white-supremacist militias grew rapidly, but the backlash to the Charlottesville rally, in 2017, proved damaging. “Since then, there has been a major shift among far-right groups, white nationalists, and militias toward espousing Christian nationalism, much like the Ku Klux Klan did,” Alexander Reid Ross, a geography lecturer at Portland State University, said. Beginning in 2018, white supremacists donned suits and appeared at conferences held by the N.A.R. and similar groups. “The tactic has been to use Christian nationalism to cool down the idea of fascism without losing the fascism,” Ross said. For example, after the white-nationalist organization Identity Evropa was dissolved, a former leader aligned himself with America First, a movement to make America a “white Christian nation.” (America First was one of the most prominent groups at the Capitol insurrection.)

A long-standing distrust of educational institutions and the mainstream media, coupled with a tradition of anti-intellectualism, has also left white evangelicals vulnerable to conspiracy theory. Many prominent conspiracy theories draw heavily on Christian-nationalist ideas; QAnon, which holds that America must be saved from a cabal of pedophilic Democrats, speaks of believers as an “elect,” and references Scripture and end-times theology. A recent study by the American Enterprise Institute found that twenty-seven per cent of white evangelicals, more than any other religious group, believe that the basic tenets of QAnon are “mostly true.” (Mastriano denies any affiliation with QAnon, though he has made several appearances on QAnon-connected media outlets.)

As a result, during Trump’s Presidency, many white evangelicals came to believe that his government, the one chosen by God, was under threat from an internal enemy: a shadowy conspiracy of leftists. And, when Trump started claiming that the 2020 election had been stolen from him, many evangelicals took up the call. According to Perry’s research, some sixty-seven per cent of evangelicals believe that the results of the 2020 election were “not at all fair.” Trump’s most powerful evangelical allies, including Franklin Graham, repeatedly undermined the results of the election. “Was there funny business in this last election? Sure there was,” Graham told me. “And there’s mountains of evidence.” Paula White, Trump’s religious adviser and a leader of the New Apostolic Reformation, held a televised campaign in which she led prayers against those with a “demonic agenda” that included “trying to steal this election.” Mastriano has likened his political agenda to that of the Old Testament figure of Esther, a queen who stopped the ancient Persians from massacring the Israelites; Mastriano said that “if we get the call, we’re not going to stand away from our Esther moment.” “His trajectory is precisely what we see in white evangelicalism,” Kristin Kobes Du Mez, a professor of history at Calvin University and the author of “Jesus and John Wayne,” told me. “Anti-communism from the late nineteen-forties to the nineteen-sixties was really the crucible in which this sense of ‘us versus them’ and militarism was formed. After 9/11, Islam became the new enemy.” She added, “Now, for some, the enemy has become the forces of secular democracy.”

As the effort to delegitimize the election heated up, Mastriano told his supporters on Facebook, “You know, when things go wrong, oftentimes Christians will say, ‘Oh, it’s God’s will,’ and kind of throw their hands. That’s nonsense. What a cop-out. Please don’t do that. This isn’t His will.” He appeared on Steve Bannon’s radio show, “War Room,” as well as on a right-wing Christian show called “The Eric Metaxas Radio Show,” during which Trump called in and said, “Doug is a hero!” In Pennsylvania, Mastriano supported a barrage of lawsuits and a bid to appoint special electors. On November 25th, he hosted a theatrical hearing in Gettysburg, featuring Rudy Giuliani as a faux prosecutor. That afternoon, Mastriano and his son drove from Gettysburg to the White House at the President’s invitation. (Mastriano tested positive for COVID-19 and was reportedly ushered out of the meeting with Trump.)

On December 12th, Mastriano returned to Washington, D.C., to participate in a series of “Jericho Marches” organized by leaders of the New Apostolic Reformation in which conservative Christians, among a hodgepodge of QAnon followers and white nationalists, gathered to pray that God would keep Trump in office. Alex Jones, of Infowars, attended, as did members of the Oath Keepers militia. Participants dressed in Colonial knickers, to evoke the American Revolution, or in animal skins, to evoke the Israelites. Jack Jenkins, a reporter for Religion News Service, told me, “They blew on shofars”—ram’s horns that Israelite priests blew, according to the Bible, to bring down the sinful city of Jericho—“believing they could literally overturn the election results.” Mastriano exhorted his followers to “do what George Washington asked us to do in 1775. Appeal to Heaven. Pray to God. We need an intervention.” The phrase “appeal to heaven” comes from John Locke’s argument in support of the right to violent revolution in the face of tyranny. “An Appeal to Heaven” appeared on a flag that a squadron of George Washington’s warships reportedly flew, and has grown popular among N.A.R. members. Mastriano has hung a sign reading “An Appeal to Heaven” on his office door, and the flag sometimes appears behind him during his fireside chats. He told his followers that laws and governments made by man needn’t always be respected, reminding them that Hitler, too, was an elected official.

Many who hold Christian-nationalist beliefs think that God’s will should determine America’s course. “Christian nationalists take the view that because America is a ‘Christian nation,’ any party or leader who isn’t Christian in the ‘right’ way, or who fails to conform to their agenda, is illegitimate,” Katherine Stewart, the author of “The Power Worshippers,” told me. “Legitimacy derives not from elections or any democratic process but from representing an alleged fidelity to their version of the American past and what they believe is the will of God.” As a result, overthrowing an election, if it seems to have subverted God’s will, would be justified. “That kind of anti-democratic ideology made it very easy for these radicals to imagine they were being patriotic, even while they were attacking the most basic institutions of democracy: the U.S. Congress and the election process.”