Racism is a poison that has flowed through the American body politic since before the founding of the republic. The United States was founded on two great sins: the enslavement of black people and the genocide of Native American people. Donald Trump, to say the least, has not tried to find a cure for this poison. Instead he has injected more of it into the country.

This article first appeared in Salon.

Trump has done this in many ways. In general, he wants to reduce and ultimately take away the civil and human rights of nonwhites and Muslims. Trump and his administration are also committed to undermining the basic assumption that nonwhites and Muslims (as well as LGBT people and other marginalized groups) have the same equal protections under the law as white heterosexual Christian men.

Some specific examples: Trump embraces racism and white supremacy through his slurs against Latino and Hispanic immigrants and refugees as a "race" of rapists, gang members and killers. As a matter of policy his administration has put babies and children in concentration camps with the goal of causing them and their families harm in order to deter "illegal immigration" into the United States.

Trump's white identity politics agenda is prefaced on ensuring that white people remain the dominant social, political and economic group in the United States. He believes that the people of Puerto Rico -- a U.S. commonwealth where at least 5,000 people died in the wake of Hurricane Maria -- are lazy and do not deserve assistance. As shown by Donald Trump's other behavior, his attitude is likely rooted in animus towards nonwhite, Spanish-speaking people -- who are also more likely to be Democrats.

He suggested after the 2017 riots in Charlottesville, Virginia, that at least some of the neo-Nazis, Klan members and white supremacists who gathered there were "very fine people." These same white supremacists, hate-mongers and domestic terrorists have claimed Donald Trump as their hero and champion.

The FBI, the Southern Poverty Law Center and other organizations have documented a large increase in hate crimes and other right-wing political violence beginning with Donald Trump's campaign and through to the third year of his presidency. In 2018 there were at least 1,020 hate groups in the United States. This is a record number, one that has only increased during Trump's time in office. As seen in incidents across the country, this hate groups have too often unleashed lethal violence.

In total, the president of the United States helps to set the moral tone for the nation. In that role he or she gives permission, both active and tacit, for individuals' and the public's behavior.

New research by University of North Texas political scientists Ayal Feinberg, Regina Branton and Valerie Martinez-Ebers offers additional evidence on the relationship between Donald Trump and racial violence in America. Their new paper, "The Trump Effect? Political Rallies and Hate Crime Contagion," will be presented at the 2019 meeting of the Western Political Science Association.

Writing in the Washington Post, the authors explain their methodology, writing that they examined a possible correlation "between the counties that hosted one of Trump’s 275 presidential campaign rallies in 2016 and increased incidents of hate crimes in subsequent months." They included numerous controls for such factors as crime rates, minority populations, educational levels and documented numbers of hate groups prior to the Trump rally.

Feinberg, Branton and Martinez-Ebers summarize their conclusions this way:

We found that counties that had hosted a 2016 Trump campaign rally saw a 226 percent increase in reported hate crimes over comparable counties that did not host such a rally.

Of course, our analysis cannot be certain it was Trump’s campaign rally rhetoric that caused people to commit more hate crimes in the host county. However, suggestions that this effect can be explained through a plethora of faux hate crimes are at best unrealistic. In fact, this charge is frequently used as a political tool to dismiss concerns about hate crimes. Research shows it is far more likely that hate crime statistics are considerably lower because of underreporting.

Additionally, it is hard to discount a “Trump effect” when a considerable number of these reported hate crimes reference Trump. According to the ADL’s 2016 data, these incidents included vandalism, intimidation and assault.

What’s more, according to the FBI’s Universal Crime report in 2017, reported hate crimes increased 17 percent over 2016. Recent research also shows that reading or hearing Trump’s statements of bias against particular groups makes people more likely to write offensive things about the groups he targets.

I asked several of the country's leading experts on psychology and violence to help me better understand the broader context of this new research about Donald Trump, his movement and political violence.

Dr. Bandy X. Lee, professor of psychiatry at Yale University and lead editor of the bestselling book "The Dangerous Case of Donald Trump: 27 Psychiatrists and Mental Health Experts Assess a President."

This is not surprising and, in fact, is likely only the tip of the iceberg.  What we know about violence is that it is modeled and learned. Ecological studies also show us that even individual violence results more from social, cultural, economic and political factors than individual factors. Rhetoric that encourages or glorifies violence, especially coming from an authority figure, is exactly how we would expect society-wide epidemics of violence to begin.

Leaders with psychological structures such as Mr. Trump's, especially, will pick up on these patterns more quickly than others, and use it to their advantage — intentionally and enthusiastically — as they want violence to retain their power.  Violence confirms their worldview, fuels their desire for cruelty, and thrills them with a sense of strength, which compensates for an intolerable inner experience of inadequacy. The most lethal and pervasive forms of violence are hidden and enduring. As such, we can expect the true death and injury toll from a culture of violence to be felt years after Mr. Trump’s final years in office.

We could say that hatred had been suppressed, at least in the sense of open hate speech, but Trump in his rallies encouraged his audiences to give in to what they had been suppressing. ... We shouldn’t be surprised by these very clear statistics; the closer the community was to Trump’s grandiose paranoid hate the more likely that individuals in that audience are likely to feel they are entitled to act violently to get rid of those they feel so much deserve their hate.

Dr. Henry J. Friedman, associate professor of psychiatry, Harvard Medical School. He is also on the editorial boards of the American Journal of Psychoanalysis, Psychoanalytic Quarterly and the Journal of the American Psychoanalytic Association

While Donald Trump has focused on illegal immigrants as those who contaminate and destroy American greatness, his followers, who frequently have no contact with illegal immigrants, have a backlog of hatred for Jews, blacks and LGBTQ individuals, the usual targets of white supremacy, because it is these groups that have traditionally been the target of hatred.

During the Obama administration there was a public force exercised against racism and anti-Semitism, a force that inhibited even those who were filled with hatred for those outsider groups. The resultant containment of these hatreds, the view that they were no longer acceptable if uttered aloud, gave way to the Trumpian endorsement of hatred of illegal immigrants.

The resultant containment of these hatreds, the view that they were no longer acceptable if uttered aloud, gave way to the Trumpian endorsement of hatred of illegal immigrants. We could say that hatred had been suppressed, at least in the sense of open hate speech, but Trump in his rallies encouraged his audiences to give in to what they had been suppressing. ... We shouldn’t be surprised by these very clear statistics; the closer the community was to Trump’s grandiose paranoid hate, the more likely that individuals in that audience are likely to feel they are entitled to act violently to get rid of those they feel so much deserve their hate.

Dr. Philip Zimbardo is professor emeritus of psychology at Stanford University. He is the author of more than 400 articles in professional journals as well as the book "The Lucifer Effect: Understanding How Good People Turn Evil." Zimbardo was also the creator of the famous (or infamous) "Stanford prison experiment."

Hatred of others who appear different from the majority has been common in many nations around the world. Less common is translating that negative emotion into hostile, even deadly actions against these "Others."

One motivation for doing so is to show your superiority over those who are deemed inferior because of their race, religion, gender or ethnicity. It is easier and safer for such individuals to instigate hostile, deadly actions when submerged in a group of like-minded peers.

Such collectives congeal around their political leaders’ rhetoric that provides righteous justification of suppressing these defiled minorities by all means necessary.

Two of the contributors to this collective violence are their public reporting in the media that serve to incite them by social modeling of what is seemingly the right way to be a "good old American," and also our president, Donald J. Trump! The statistical evidence is his clear indictment: In all counties where he has held public rallies the hate crime index is significantly greater than in counties where Trump was in absentia.

Dr. James Gilligan is an adjunct professor at the New York University School of Law. He is the author of several books, including "Why Some Politicians Are More Dangerous Than Others" and "Violence: Reflections on a National Epidemic." 

During his rallies, beginning during his campaign for the presidency, Trump has repeatedly urged his followers to punch those who did not agree with him in the face and beat them up so badly that they’d have to be taken out on stretchers, with remarks like the following:

“I’d like to punch him in the face, I’ll tell you.”

“In the good old days this doesn’t happen, because they used to treat them very, very rough.”

“I love the old days. You know what they used to do to guys like that when they were in a place like this? They’d be carried out on a stretcher, folks.”

“If you see somebody getting ready to throw a tomato, knock the crap out of them, would you? Seriously. Just knock the hell out of them. I will pay for the legal fees, I promise you.”

He even complained that his supporters were not being violent enough. Then he amplified the magnitude of violence that he urged his followers to commit when he reminded them that they could always assassinate Hillary Clinton if she were elected president. In his words, “If she gets to pick her judges, nothing you can do, folks. Although the Second Amendment people -- maybe there is, I don’t know.”

And so on and on and on, in an endless stream of threats of violence, boasts of violence and incitements to violence.

Given those and many other examples of his attempts to incite his supporters to commit an ever-increasing scale of violence, it is far from surprising that they have done just that. Indeed, given that he is their authoritarian leader, the only thing that would be surprising would be if they did not do so.

Virtually every major mass-murderer who has committed hate crimes, both in this country and others, has referred to Trump as their leader and example, including the man who murdered 11 people in the Pittsburgh synagogue (and wounded four police officers); the man from Florida who mailed bombs to several Trump opponents such as Hillary Clinton, Barack Obama, George Soros and others; the man who killed a woman and grievously injured many others by driving his car into pedestrians in Charlottesville, Virginia; the man who killed people in two mosques in New Zealand; and so forth, on and on.

That these individual examples are not just “cherry-picked,” atypical or exceptional anecdotes has been shown by the recent quantitative, statistical finding that the American counties that hosted a Trump campaign rally in 2016 experienced an increase in reported hate crimes that was more than three times higher than in comparable counties that had not hosted such a rally.

*  *  *

During the 2016 presidential campaign Donald Trump infamously bragged that he could shoot someone in broad daylight on Fifth Avenue and still get elected. It would seem that he was correct. But Trump's claim was more than a boast: For his supporters, it was an encouragement to violence. Such violence is infectious, and President Trump is America's most prominent disease carrier.