The opinions expressed by columnists are their own and do not necessarily represent the views of Townhall.com.

Donald Trump’s victory over one of the most powerful political machines in American history has given mainstream America the opportunity to turn America onto a sensible course. The success or failure of that turnaround, however, depends largely on the ability of mainstream Americans to see through the left’s longstanding use of a vile political tactic known as gaslighting.

The word gaslighting has been popularized in psychology to describe a form of mental and emotional abuse in which a domineering person denies and contradicts the memories and perceptions of an intended victim until the victim begins to doubt his or her perception of reality. The word comes from the 1944 mystery film Gaslight, in which a woman’s husband tries to convince her that she is losing her mind and that the things she is experiencing – such as the gaslights in the house flickering and dimming – are not real. Only when an inspector from Scotland Yard also notices the gaslights flickering does she realize that she is not losing her mind and that her husband has a devious agenda.

In politics, the word “gaslighting” is increasingly used to describe the left’s efforts to push a false view of reality and to convince mainstream Americans that their common-sense views are somehow extreme. For example, on a recent edition of Varney & Co., Rep. Louie Gohmert (R-TX) said the Obama administration’s portrayal of Israel as our enemy and Iran as nothing to worry about could be described as “gaslighting.” Bill Whittle’s popular video Gaslighting exposed the left’s use of the gaslighting tactic to spread false information about issues such as Benghazi and Obamacare.

Note that gaslighting is a far more insidious tactic than political spin. Spin merely attempts to shift the interpretation of a real situation by presenting it in a different light. Gaslighting presents a completely false alternative to reality and is intended to erode the confidence of the target in his or her own perception.

Imagine two people standing outside in a severe rainstorm.

SPIN: “You say this is a downpour? It looks more like a heavy sprinkle to me.”

GASLIGHTING: “You say this is a downpour? What are you talking about? It’s sunny and pleasant. Are you feeling OK? You’re acting a little strange.”

Because it presents a false picture of reality, two elements are especially important for gaslighting to succeed. First, those doing the gaslighting must display confidence and audacity in pushing their view of reality and must persevere boldly in the face of evidence that contradicts their claim. Second, the target must be psychologically isolated and denied validation by others who see the same reality. The left’s dominance in the cultural institutions of education, news, and entertainment has given them both elements.

Consider the video by the Family Policy Institute of Washington in which Seattle University students were asked if there’s a difference between men and women. Instead of answering, “You’re kidding me, right?” these students actually took the interviewer’s question seriously and, even worse, they struggled to answer it. Some went so far as to parrot the far left’s narrative that the distinction between male and female is merely a social construct imposed on people by society and that it has no real significance otherwise.

Has news about who has the babies not reached Seattle? Or have those students been so browbeaten by the gaslighting of their leftist professors and the leftist culture on campus that they are hesitant to admit publicly to what their own eyes, their own bodies, and their common sense tell them?

That is the power of gaslighting, and the left’s institutions have been audacious in using it against those who question their agenda.

In the left’s alternate reality, the police are threats to law and order and rioters are victims of the system. Mainstream Americans who supported Trump are ridiculed as “anti-immigrant” even though we made an immigrant our next First Lady. The belief that refugees should be carefully vetted in order to keep more terrorists from exploiting our generosity is attacked as “xenophobic.” And leftists casually use both “homophobic” and “Islamophobic” to attack their opponents without even a moment’s reflection on Islam’s position on homosexuality.

After all, in gaslighting, it is the effect of words on the intended target that counts and not the truthfulness or logical consistency of those words. If the target is isolated, demoralized, and fearful of opposing the left’s agenda, the tactic has worked.

One of the reasons for Trump’s Electoral College landslide was that he validated what tens of millions of Americans had been thinking in spite of the gaslighting efforts of the left. The light of liberty has indeed been flickering. We weren’t just imagining things. The political elite really did have an agenda other than promoting the interests of the American people. We weren’t crazy.

With their power threatened, the left’s gaslighting has passed audacious and become desperate. A man who has never held elective office just trounced the Clinton machine and their echo chamber in the media. And what does the left tell us? The Russians did it.

Get ready for more.