A Halloween mask depicting Donald Trump is seen for sale at Total Party, a party store, in Arlington on Oct. 7. (Saul Loeb/Agence France-Presse via Getty Images)

Critics of Donald Trump often invoke the concept of monstrosity. Trump is either characterized explicitly as monstrous (e.g. “Trump is the GOP’s Frankenstein monster”) or more implicitly as abnormal, deviant and warped (e.g. an “abomination”). That includes reactions to the Access Hollywood tape, in which he was recorded talking about grabbing women by their genitals, and to subsequent allegations of sexual assault: Many cast Trump as a man of “monstrous” appetites.

This monster discourse isn’t just a symptom of Halloween. Monsters offer a way of metaphorically encoding threats, which makes them useful political tools.

George Lakoff, a cognitive linguist, argues that metaphors in political discourse operate on us unconsciously. They help us make symbolic connections that put events and people in context, shaping our understanding of the social and political world. Looking closely at the many monstrous characterizations of Trump shows us that monsters are functional metaphors. Examining how and why his behavior is defined, by some people, as monstrous teaches us about the psychology of voters and the strategic behavior of political elites.

Here are three insights into political monsters and the functions they perform.

1. Monsters moralize and mobilize.

Monster discourse reflects two important social psychological processes: dehumanization and moral distancing. According to psychologist Nick Haslam and his colleagues, morality and humanness are closely intertwined.

Dehumanizing language, such as the monster narrative, clarifies boundaries between groups so that perceptions of moral distance between groups widen. This dynamic is particularly pronounced in groups that are defined in relation to one another, as with the political left and the political right.

So, for instance, Senate Minority Leader Harry M. Reid (Nev.), a Democrat, said that Trump “is the monster the Republicans built. He is their Frankenstein monster.” He’s dehumanizing and creating moral distance, assuring his constituents that the sentiments Trump mentions belong only to the Republican other.

Defining someone as a monster, and therefore outside a moral boundary, helps a group build its own moral identity and strengthen its own group attachments. Pointing at an outside monster reminds people of their shared commitment to core values — and mobilizes them against the threat. Although researchers have yet to empirically link monster narratives specifically to political behavior, the psychological research on moral distancing is suggestive. Italian psychologist Maria Giuseppina Pacilli notes that “moral differences are more socially divisive than other classes of differences,” and can “aggravate intergroup conflict.” Research on dehumanization also shows that people who seem morally distant may be seen as less human, which makes violence against them seem more acceptable.

Thus calling someone a monster is not only a political tool but also testifies to our own monstrous potential.

2. Monsters deflect and redirect.

For Republicans, monster narratives make it easier to distance themselves from Trump’s racial and gendered comments without much self-examination. Trump states directly that a variety of racial and ethnic groups threaten white Americans. For instance, he calls for a ban on Muslims entering the country, claims Mexicans who wish to cross the border are rapists and criminals, or equates life in the inner cities to living in hell. Until now, the Republican Party has conveyed such threats in far more coded language.

Casting Trump as a monster is an effort to distance the party from what some researchers claim is its long history of “playing the race card” when appealing to its base. It defines Trump as deviant for using a more explicitly racial discourse — pointing to the differences between him, other GOP elites and the party base rather than to their similarities.

It allows them to reject Trump and use moral outrage to distance themselves from political rhetoric they don’t necessarily disavow. The Trumpenstein image is an attempt to draw a stark distinction between the candidate and the party. However it’s a distinction that isn’t really there.

In political monster narratives, the monster doesn’t always destroy the system that created him. Sometimes he is destroyed to keep the system intact. Defining him as a monster seems to carve the problem from the system from which it is entangled, and offers a target that can be destroyed without bringing the whole system (or party) down with it. The monster makes a convenient scapegoat.

English professor Jeffrey Jerome Cohen, author of “Monster Theory,” writes: “The scapegoated monster is perhaps ritually destroyed in the course of some official narrative, purging the community by eliminating its sins. The monster’s eradication functions as an exorcism and, when retold and promulgated, as a catechism.” But destroying the monster — which in Trump’s case means electoral defeat — doesn’t in fact purge the sins assigned to it. It’s only a symbolic victory — one that distracts from the problems that remain.

3. Monsters destroy but also create.

The final lesson of monster discourse is that monsters have many kinds of power, both destructive and creative. Critics of Trump seem to suggest that he is both a monster and a monster maker. Some observers believe that Trump may destroy the Republican Party. Others are concerned that he may be bringing forth a more robust white nationalist movement.

Monster discourse isn’t just hyperbole. It shapes our thinking.

The monster politics invoked throughout this election reveal that our nation’s political polarization results not so much from competing principles and policy priorities but from identity politics and categorical prejudices. Our political monsters tell us something about who we are as a nation and reveal the challenges we face in living up to our nation’s egalitarian commitments.

Monstrous language is strategic and powerfully shapes voters’ imaginations. As philosophy professor Stephen Amsa wrote in his book “On Monsters,” “Monsters, both real and imagined, are bound up with our feelings of insecurity and our responses to those anxieties.”

This election has laid bare many fears that once lurked uneasily beneath the surface of public life. Regardless of the outcome, those monsters will still be with us on Nov. 9.

Erin C. Cassese is an associate professor of political science at West Virginia University, currently working on a project tentatively titled “The Political Psychology of Monstrosity.”