On a recent episode of "Last Week Tonight," comedian John Oliver shared an unsettling encounter he’d had with Republican presidential front-runner and reality TV star Donald Trump.

Trump declared last year that he’d turned down an invitation to appear on Oliver’s show. "John Oliver had his people call to ask me to be on his very boring and low rated show. I said 'NO THANKS' Waste of time & energy!" he wrote in quintessentially Trump tweet.

According to Oliver, that simply never happened. No one at his show had invited Trump to be a guest. But Trump doubled down. In a radio interview, he outlandishly maintained that he’d been asked "four or five" times to appear on "Last Week Tonight."

Oliver was rattled.

"It was genuinely destabilizing to be on the receiving end of a lie that confident," he said on air. "I even checked to make sure that no one had even accidentally invited him, and of course, they hadn’t."

Trump’s claim was delivered with such gusto that Oliver began to doubt what he knew to be true, even though he knew Trump was lying.

That’s the power of gaslighting.

This form of psychological abuse typically plays out like so: The gaslighter states something false with such intensity and conviction that whoever is on the receiving end is confused and begins to doubt their own perspective.

The term comes from a 1938 play called Gaslight, in which a husband drives his wife crazy by secretly altering things in her house and making her question her grip on reality.

As Nicole Hemmer eloquently argued in a piece for U.S. News And World Report, Trump is a classic gaslighter -- and his target is all of us. She writes:

Trump is a toxic blend of Barnum and bully. If you’re a good mark, he’s your best friend. But if you catch on to the con, then he starts to gaslight. Ask him a question and he’ll lie without batting an eye. Call him a liar and he’ll declare himself “truthful to a fault.” Confront him with contradictory evidence and he’ll shrug and repeat the fib. Maybe he’ll change the subject. But he’ll never change the lie.

When faced with their brazen lies, gaslighters deny their own statements, change the subject, lash out with insults (think "little" Rubio and "liar" Cruz), act indignant about the accusation, or turn on the messenger -- which, for Trump, is often the national media.

According to Robin Stern, associate director for the Yale Center for Emotional Intelligence and author of The Gaslight Effect: How to Spot and Survive the Hidden Manipulation Others Use to Control Your Life, Trump is exhibiting textbook gaslighting behavior.

"When you don't take responsibility for your actions, or deflect responsibility, or try to undermine the credibility of the person asking you about your actions, that's gaslighting," she said.

Trump has said a lot of things that are simply untrue, with varying degrees of consequence.

According to a Politico analysis of a week's worth of his speeches, Trump tells a falsehood, on average, once every five minutes. It's hard to keep up with that many untruths, but Politifact has a good running compilation.

Yet despite his history of patently false statements, neither his opponents nor reporters have had much luck calling him out.

Stern said it's extremely difficult to get gaslighters to take responsibility for their actions, because instead of expressing shame or contrition, they are likely to feign outrage and attack the questioner.

"You might be confronting the person on their own behavior, but they will immediately turn you into the problem," she said. "It can be extremely damaging to your sense of self and psychological stability."

While there’s no particular personality type that is more likely to employ gaslighting, Stern said the technique is often used in abusive relationships.

So what should the country do?

According to Stern, the best way to handle a gaslighter is to disengage and let go of the relationship.

"Confronting the gaslighter can inflame him," she said. "You can not win that power struggle with someone who is invested in gaslighting. With some people, it’s hard to penetrate their system, if not impossible."

With Trump inching ever closer to the GOP nomination, the only way for America to break off the relationship is to show up at the polls and vote him down.

Editor's Note: Donald Trump is a serial liar, rampant xenophobe, racist, misogynist, birther and bully who has repeatedly pledged to ban all Muslims -- 1.6 billion members of an entire religion -- from entering the U.S.

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Melissa Jeltsen covers domestic violence and other issues related to women's health, safety and security. Tips? Feedback? Send an email or follow her on Twitter.

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