One startling feature of the latest race to become the next president of the US - which begins in earnest with next week's Iowa caucuses - is the runaway success in the opinion polls of the outspoken billionaire, Donald Trump. But this should not be so surprising, says Michael Goldfarb, as Trump is just the latest example of a tendency in American politics that goes back a very long way.
The simple four-letter word that works if you want to get elected. Political professionals know that playing on people's fears - going negative - is the way to win.
A somewhat fancier word that is used to describe excessive, irrational fear and distrust. It, too, works from time to time - in American politics, at least.
This current presidential season is one of those times. Donald Trump has surged to the front of the pack competing for the Republican Presidential nomination by giving voice to outsized fears many in America have - of illegal immigrants, of Islamic terrorists, of free trade agreements shipping American jobs to China.
Trump promises to make America Great Again - as if the US somehow was no longer the most powerful country in the world - by simple solutions: deporting all 11 million illegal immigrants, banning Muslims from entering the US, and forcing the Chinese government to back down through tough talk.
The phrase "paranoid style in American politics" was coined by the late historian Richard Hofstadter. He defined the Paranoid Style, "an old and recurrent phenomenon in our public life which has been frequently linked with movements of suspicious discontent."
In a country that at its best radiates an infectious optimism, it is interesting how often fear has stalked the American landscape.
Richard Parker, who lectures on religion in the early days of America at Harvard's John F Kennedy School of Government, traces paranoia in American public life back to the Salem Witch Trials in the late 17th Century and even before that, to the religious politics of the Mother Country.
It's easy to forget how closely tied the first colonies were to England, particularly in Massachusetts. The Pilgrims were dissenting Protestants who sided closely with Cromwell in the English Civil War. When the Commonwealth was overthrown and the Stuarts restored to the British throne, there was renewed struggle with Catholicism - and the religious suspicions surrounding the court of James II were magnified out of all proportion on the other side of the Atlantic.
Add in the daily struggles with nature, fighting with native Americans, and millennial religious practice that thought the end times were approaching and you have, Parker points out, "a community primed to be fearful".
And so in the town of Salem, people turned on their more free-thinking neighbours, and accused them of being witches. At this time, the idea of witchcraft was not something from fiction. People really did believe, in Parker's words, "dark spirits could inhabit souls and bodies. It was the basis for primitive psychology and physiology."
He adds that it's no surprise that in 1953, playwright Arthur Miller set his classic drama, The Crucible, in Salem during the witch trials.
The early 1950s was a time of another outbreak of fear in America, this time of communists in high places everywhere including the entertainment industry. There were blacklists of suspected communists and former communists in Hollywood. The House Un-American Activities Committee summoned the famous to Washington to testify against artistic colleagues. Careers were ruined. Miller, summoned by the committee in 1957, refused to name names and had his passport revoked.
Another source of fear that recurs in American history is of the secret society in league with foreign powers. Many of America's first presidents were Freemasons and masonry was closely associated with the French Revolution. Later on the concern was cabals of foreign bankers trying to destroy the American working man's livelihood.
But religion is the playing field for most of these fears.
In the early days of the Republic, Roman Catholics were suspected of being the vanguard of a Papist plot to take over the country. The fact that in the first census, of four million citizens only 25,000 were Catholic didn't matter. In the late 1840s, a huge wave of Catholics fleeing the famine in Ireland only inflamed suspicions.
A new political party was formed, called the Know Nothing party. It grew out of a secret society, whose main creed was anti-Irish immigration. Its members were told to say, if asked about it, "I know nothing." Hence the name.
The next group to be suspect was the Jews, whose great immigration wave came at the turn of the 20th Century. The entire Jewish immigrant population, some of whom were socialists, many of whom came from Russia, became conflated with the Russian Revolution.
By the 1930s, in his weekly radio broadcast, a Catholic priest, Father Charles Coughlin, an Irish Catholic, was whipping up fear about Jews and their "communising the factories and the fields and the mines".
Following World War Two the fear shifted to the Soviet Union. Leaders of the far-right vied with each other to see who could turn up the most Communists. This led Robert Welch, the founder of the ultra-right John Birch Society, to claim that President Dwight D Eisenhower was "a tool of the communists".
Welch was disowned by American conservatives for that assertion, yet his organisation became the foundation of a grassroots political movement that has dominated American politics for the last four decades. In her book, Suburban Warriors, Harvard history professor Lisa McGirr charts the rise of "movement conservatism" in the new suburbs of Orange County California, just south of Los Angeles.
Find out more
Listen to Michael Goldfarb's radio documentary, Trump and the Politics of Paranoia, on BBC Radio 4 at 20:00 on Monday 25 January, or catch up later on the BBC iPlayer.
Many of these conservatives had no problem with the Birch Society's extreme fear-mongering about an imminent Communist takeover of the US. It was observing the growth of this new movement that led Richard Hofstadter to write his seminal 1964 essay, The Paranoid Style. But McGirr disputes the idea that their "apocalyptic strands of thought" were a form of paranoia.
"Hofstadter makes a mistake in presenting an overly psychological, clinical portrait, which has the tendency to lead to a dismissive characterisation of their ideology," she says.
"I think it is linked to religiosity: evangelicalism and fundamentalism which have deep strands in American life," she adds, echoing Richard Parker.
"Hofstadter wanted to write them off but they cannot be written off, they are an important strand of American life which survives to this day."
Writing off Donald Trump was the default setting of most pundits and political professionals in the first months of the campaign. It isn't any more. Trump understood more than they did that a significant chunk of American society is fearful. He plays to those fears - whether they are rational or not. He doesn't speak in what he calls "politically correct" terms.
In South Carolina, recently, I met a gentleman named Robert Sandifer. In his 70s, well-educated and well-off, he had retired to a lovely island just south of Charleston, one of the nicest cities in America.
"Trump has instilled hope in people," Sandifer told me.
"Hope? Sounds to me like desperation," I told him.
Sandifer politely disagreed. "If he does what he says he's gonna do, we would be less fearful." He added, for emphasis: "We fear the federal government very much."
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Michael Goldfarb is the author of Emancipation: How Liberating Europe's Jews from the Ghetto led to Revolution and Renaissance.
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