When Franklin Delano Roosevelt told a Depression-ravaged America in 1933 that “the only thing we have to fear is fear itself,” he couldn’t have imagined 2015.

It’s not just San Jose high-tech purchasing agent Mike D’Amelio who evokes the fear when he reels off a list of the reasons he’s supporting Donald Trump for president: to “stop illegal aliens,” stop Iran from selling a nuclear weapon to “ISIS or related loons,” stop the government from taking citizens’ guns.

In this Year of Fear, the politics of trepidation are spreading across the spectrum, fueled by rhetoric on the campaign trail that is seeping into people’s lives and boomeranging back into poll numbers that reaffirm how keeping America safe is Priority No. 1.

Cindy Wilson feels it. The Oakland mother of two teenagers, a Democrat, said she has never liked crowds, but mass shootings and all this talk about terror have her looking even further over her shoulder.

“I have no desire now to go into San Francisco and do the Christmas shopping thing,” she said. “I’m always looking around. I’m much more aware of my surroundings.”

Fear of harm is only natural, even if some who harbor it might realize deep down that the risks are exaggerated. But calm and contemplation have found little foothold this year, as the usual “us vs. them” rhetoric has become more visceral.

Republican presidential hopefuls seem to be trying to corner the market on such rhetoric, but Democratic candidates addressed the fear factor at Saturday night’s debate in New Hampshire.

“Fear is a time-honored approach that political practitioners of both parties have used effectively for many, many years,” said Dan Schnur, a former GOP strategist who now directs the University of Southern California’s Unruh Institute of Politics. “If you can’t motivate people with inspiration, you can motivate them with fear. It’s not a particularly effective technique at persuading undecided voters, but it’s an extremely savvy way to motivate your base.”

Two things are different in 2015, Schnur said: terrorism and Trump.

The Islamic State’s barbaric rise and attacks in Paris and San Bernardino are examples politicians can cite to stoke voters’ fears, Schnur said, while Trump “takes this to a different level than most candidates of either party … both in the type of language he uses and in the fairly frequent inaccuracy of his charges.”

It seems to work for Trump, who has topped GOP polls for all but three days since mid-July, according to averages of national polls compiled by Real Clear Politics. As of Friday, he had 33 percent support — his highest so far.

His message is sticking with D’Amelio, who isn’t a gun owner but says he might buy one soon: “Citizens feel more than ever they need guns to protect themselves.”

Even before the Paris and San Bernardino attacks, fear of terrorism was at its strongest since October 2001, Gallup found in June, even as the Washington Post has noted that an American is more likely to be crushed beneath improperly secured furniture than to be killed by a terrorist on U.S. soil.

And if not fear of radical jihadis or hordes of illegal immigrants, perhaps it’s fear of homegrown chaos. Wilson feels conservative politicians have focused on the threat of Islamic extremism while ignoring grave harm caused by other extremists and mass killers.

“I have no qualms about having them travel the world,” she said of her kids, “but I would be afraid to have my daughter go to a Planned Parenthood clinic.”

If today’s voters won’t heed FDR’s words, maybe the current “Star Wars” mania will help them recall Yoda’s: “Fear is the path to the dark side. Fear leads to anger. Anger leads to hate. Hate leads to suffering.” But that path is risky for any politician, said Peter Ditto, a UC Irvine professor of psychology and social behavior.

“The problem is, you’ve got to ride that horse once you’ve got it, and it can get away from you,” he said, citing Republican candidates who were “amping up that fear” during Tuesday’s debate in Las Vegas.

Tough-talking candidates might win scared voters’ support in the short term, Ditto said, but that electorate could turn on them in a hurry if they can’t provide a convincing solution to the fear’s source — or if they eventually must cooperate and compromise with those they’ve criticized.

Consider the classic example: U.S. Sen. Joe McCarthy, R-Wisc., who rode the “red scare” of communist and gay infiltration to fame and power in the early 1950s, only to have his peers and the nation turn on him. Censured and disgraced, he basically drank himself to death in 1957.

Trump’s and other Republicans’ ability to capitalize on fear might be due partly to human physiology. Researchers from the University of Nebraska and Rice University published a study in 2014, which found that people who identify as conservatives tend to register greater physical responses to negative stimuli, and also think about them more, than liberals; Virginia Tech researchers published a similar finding last year.

Some say it’s the media, as seemingly round-the-clock news of violence or threats, however distant or uncommon, draws people to their televisions, computers, phones or newspapers. The presidential fear-fest has been a cash cow as GOP debates have broken viewership records: CNN sold 30-second spots for the September debate for $200,000 a pop — 40 times the normal rate — while CNBC charged as much as $250,000 per ad in October.

Antidotes are fleeting. But one remedy to fear of the unknown might be familiarity.

The long odds of being targeted in a terrorist attack are something of a comfort to Susan Audap, 69, a science and math coach at an elementary school in Concord, as is the time she spent teaching at an international school in Aleppo, Syria, decades ago. That experience gave her an appreciation for Arab cultures and people, she said.

“When you have no experience of the feared group or the demonized group, it means you have no information, and that whole thing of whipping up scaredness happens to people,” she said. “The fact that people are not being analytical at all, that they are coming totally from their guts — that’s what frightens me.”

Josh Richman covers politics. Follow him at Twitter.com/Josh_Richman. Read the Political Blotter at IBAbuzz.com/politics.