This is an awful article.  To start with it purports to be about how "...Americans endorse violence against the government" and it offers to tell us why. 

In fact, it is a loosely connected set of anti-concepts pretending to be supported by science, that winds up as an argument against making moral judgments and equating using strong words with the initiation of violence.

It opens by listing Black Lives Matter activists being shot - but they aren't government.  The Planned parenthood clinic shooting is mentioned - but again, that violence was not against the government.  And the shooting in San Bernadino, which although the people shot were employees of a county government, I wouldn't say that was an attack on the government.  So what happened to the theme of "Americans endorse violence against government"?

Notice how the author has switched from talking about "Americans endorse violence against the government" to lumping together, as if they were the same kind of violence, a shooting of a protestor that may, or may not be racially motivated, a disturbed man's actions in the Planned Parenthood shooting, and a radical Islamic terrorism act in San Bernardino.  Not only were these not against the government, and not about American's endorsing, but not even the same kinds of violence.

Next the author goes on to cite the responses to surveys, as if a poll response about taking an action has somehow already been shown as an equivalent to actually taking the action.  And the listed poll choices are about violence against the government.  What happened to the nut case talking about baby parts, or the jihadists wanting to kill infidels?  Well, there is a kind of clue in the following sentence: "This [the poll results] implies that millions of ordinary Americans endorse the general idea of violence in politics."  The clue is in the last three words: "violence in politics."  The left sees all ideology as politics and all violence related to an ideology as politics.  And they are working very hard to blur the line between words and acts, between spoken and written metaphors and actual acts of initiated violence.  The author refers to studies (which he admits are drawn from small samples).  What isn't mentioned in this article is that he is the author of the study which was part of a lead-up to the 2010 elections where he attempted to show that political violence would multiply if political ads used metaphors for violence.  (p.s., If you are interested in the study, take advantage of the link that Marotta provides in his post, otherwise will have to get out your credit card.  It is $236.)

He admits that the studies are flawed to the degree that they make "reliable statistical comparisons difficult."  You will notice that from the beginning it is the left accusing the right of verbal incitement.  That on top of a heap of mushy non-concepts, a view of human nature that precludes reasoning and choice, and his seeming inability to stay on focus (Does he really want to answer the question of whether or not American's endorse violence against the government, or has he switched to the question of, "is political language causing violence?"  He should make up his mind.)

In the study, he gets ahead of himself and foreshadows his conclusion. "Decades of research and hundreds of studies using complementary methodologies demonstrate a clear causal link between exposure to media violence and interpersonal aggression..."  So, he has already decided the issue of human nature in general and psychology in particular.  His claim: 'See violence in the media - do violence in real life.'  He takes that as settled-science and uses it as a stepping stone to making his case against using harsh words: "Although political speech may not seem as explicit or compelling as most forms of violent entertainment, psychologists have found that violent text is sufficient to promote aggression..."  More of the left's settled-science.

He goes on to say that the strongest variable is personality.  That "aggressive personality" is the strongest determinate in supporting political violence.  Now we have a real mess.  It has become "political violence" no matter the actual motives, it is still mixed up as to what this has to do with violence against the government, or endorsing, and we have the strange variable of "aggressive personality."

In this study you can see the questions he asked to measure who was "aggressive."  As someone who actually made a career in psychology I can tell you that this is nonsense on a stick.  Junk science.  Pseudo-science. 

The next absurdity is where he factors in "political disaffection."   If you distrust government, he claims, then you correlate with those who are more supportive of violence against government.  This is that grand process of using statistical correlation to ignore and sidestep essentials.  It is a way to sneak around solid reasoning by using pseudo-reasoning to create a framework that will be used in the hope of controlling language, which is how one controls thoughts and actions.  This is part of the framework for much of political correctness.

If a politiician says, "I will fight hard to get our economy back on track," that is seen as language that incites violence and he should have said, "I will work hard to get the economy back on track."  (But no doubt someone will come along and say that one shouldn't say "work hard" since it will offend those who don't have any work because of the capitalist oppression created by the white ruling class.)

The article concludes with the implication that those who use strong moral language to demonize their opponents may "facilitate moral disengagement, which allows people to rationalize the harm they do to others.  Violent acts - including terrorism - are aided by these mental gymnastics."  Wow! Who knew that morally condemning terrorists is actually aiding the terrorists.  This may point to why the left seems to want to hug those who are the most theatening - be they criminals or terrorists or dictators.  Talk about mental gymnastics!  This takes appeasement and the rejection of moral judgment to whole new levels.  And that, ladies and gentlemen, is where this article was heading from the get-go.  Coming soon: the sanction of the victim is to be made mandatory.

Sometimes I get a sense of an underlying psychology where elites see themselves as intellectually superior creatures who feel fear that the people they want to control might get upset and turn on them.