Many saw Donald Trump’s latest shocking comment, about how "Second Amendment people" might be able to do something to stop Hillary Clinton from picking the Supreme Court judges she wants, as beyond the pale. Whether or not it was a joke, the implication of his comment is pretty clear: that gun owners could use their weapons to stop either Clinton herself or liberal judges from implementing gun control.

The explicit-sounding call to violence is bad enough. But even worse is that, intentionally or not, Trump has been laying the groundwork for this idea for a while. From his talk of "rigged elections" to his suggestion that we need Russia to hack Clinton’s emails if the Justice Department won’t indict her, Trump’s message is clear: Clinton is so corrupt, and the system that favors her is so broken, that our ordinary democratic and legal processes aren’t equipped to handle it. She should be thrown in jail, but she probably won’t be.

It’s a pretty short step from that idea to violent fantasies of going outside the law for real justice — even from official sources like the Republican Party of Riverside County, California, which recently tweeted a picture of a hangman captioned "Ready For Hillary."

And there’s an unsettling parallel for this kind of rhetoric and what it can lead to, as law professor David S. Cohen pointed out Wednesday in a Rolling Stone op-ed: anti-abortion terrorism.

Cohen, who has studied and written about violence and intimidation against abortion providers, points out that while anti-abortion violence is usually carried out by a "lone wolf" — like the Planned Parenthood shooter in Colorado Springs — it’s also incited, quite predictably, by the inflammatory rhetoric of prominent groups or officials.

Cohen says that this phenomenon is called "stochastic terrorism": using language and other forms of communication to incite random acts of violence that are "statistically predictable but individually unpredictable." It’s not a legal term, but it can help us understand just how dangerous Trump’s statements are:

Let's break that down in the context of what Trump said. Predicting any one particular individual following his call to use violence against Clinton or her judges is statistically impossible. But we can predict that there could be a presently unknown lone wolf who hears his call and takes action in the future. Stated differently: Trump puts out the dog whistle knowing that some dog will hear it, even though he doesn't know which dog.

Planned Parenthood itself is explicitly making the connection between Trump’s remarks and last year’s attack on its clinic. "Words matter, and calls for violence are not a joke," Planned Parenthood Action Fund vice president Dawn Laguens said in a statement. "Planned Parenthood’s brave medical professionals and staff members know all too well how violent rhetoric can lead to real tragedy."

It’s a pattern that abortion providers in particular have seen play out time and again. Public figures or advocates demonize a person or group as a loathsome, inhuman monster, often using violent imagery and righteous rhetoric — like comparing abortion to slavery, or saying it’s worse than the Holocaust. Then when someone commits the act of violence that many people would consider an appropriate response to such extreme atrocities (who wouldn’t kill Hitler if they had the chance?), those same public figures react with shock and say that no one could have predicted this.

But it’s very predictable, statistically if not individually. Right after a series of anti-abortion videos made the baseless claims that Planned Parenthood is staffed by "butchers" who "sell baby parts" — claims that were then repeated incessantly by Republican officials and lawmakers — violent threats against abortion providers skyrocketed, and the FBI took notice. And pretty soon, Robert Lewis Dear was ranting about "baby parts" after killing three people and wounding nine at a Planned Parenthood.

Trump has suggested before that Hillary Clinton might be a murderer. But his obsessions with how "crooked" Hillary is and how the system is "rigged" to favor her may actually be more relevant here, and more dangerous.

In the years before Dr. George Tiller was murdered in his church in Kansas, anti-abortion groups like Operation Rescue conducted a relentless campaign against Tiller, calling him "Tiller the Killer" and demanding that he be jailed. Some activists went so far as to distribute "Wanted" posters featuring Tiller’s picture and address. Operation Rescue also gathered enough petition signatures to take advantage of a state law that let citizens force a grand jury trial, although there were no indictments from either of the two grand juries convened as a result of citizen petitions. Tiller was also tried, and acquitted, on charges of illegal abortion brought by the attorney general of Kansas.

But after Tiller was acquitted, Operation Rescue and its president Troy Newman continued to insist that it wasn’t over, and that Tiller still had to be "brought to justice" through some other means. Newman (who has argued before that murdering abortion doctors may be justifiable) also pushed conspiracy theories that Tiller had bought off the local district attorney or other politicians with "blood money."

Tiller’s murderer, Scott Roeder, had some connections to Operation Rescue and shared the group’s obsession with Tiller’s trial. To be clear, Operation Rescue disavowed Roeder and said he was never "a member, contributor, or volunteer" with the organization. But many critics said that it didn’t matter whether Roeder was actually affiliated with the group: Operation Rescue had relentlessly, and recklessly, pushed the narrative that Tiller was not just a murderer and a criminal, but a murderer and a criminal who was thwarting our normal system of justice. It was only a matter of time before someone took that message to heart and acted extrajudicially.

As my colleague Dara Lind has pointed out, Trump is tapping into powerful forces that he can’t necessarily control with his constant drumbeat of delegitimizing rhetoric. And if Trump is actively egging those forces on, there are predictable consequences to his behavior.

Update: This article has been updated to clarify the circumstances around Tiller's trial and the citizen grand juries convened against him.

This election is about normal vs. abnormal