As the House debated whether the Republican congressman Paul Gosar should be censured for depicting the murder of his colleague, one Democratic leader took a moment to reflect on the chamber’s long history of violence.

Speaking on the House floor last week, the majority leader, Steny Hoyer, argued that Gosar had grossly violated the chamber’s rules of conduct by sharing an altered anime video showing him killing Congresswoman Alexandria Ocasio-Cortez and attacking President Joe Biden.

“When those rules were written, they did not anticipate that a member would threaten violence directly against another member,” Hoyer said. “Not because it’s never happened – a congressman from South Carolina nearly beat to death a senator from Massachusetts, Senator Sumner, because he wanted to abolish slavery.”

The 1856 caning of Charles Sumner by Preston Brooks is probably the most infamous example of violence between members of Congress, but it is far from the only one. In her book, The Field of Blood: Violence in Congress and the Road to Civil War, the Yale history professor Joanne Freeman details the many threats and attacks between lawmakers during the antebellum era.

The Guardian spoke to Dr Freeman about the history of congressional violence and what it can tell us about the current state of US politics and the significance of Gosar’s censure. This interview has been edited for length and clarity.

Besides the caning of Sumner, what were some of the other examples of congressional violence in the pre-civil war era?

The research that I did revealed there were at least 70 violent incidents in the House and in the Senate. Some of them were canings. Some of them were fist fights. Some of them were actual brawls with groups of congressmen. In the well of the House where we saw [Gosar’s] censure take place, that was actually a location for several fights in those decades before the civil war.

And there was a lot of deployment of threats and intimidation. Most of these were offered by southerners and usually were deployed against people who had anything to say against slavery. Obviously the goal of that was to silence people or intimidate people so they wouldn’t even stand up to say anything that was not going to be to the liking of southerners.

What effect did those threats have on public debate over slavery in Congress?

There’s a diary entry from a very prominent, very aggressive anti-slavery advocate, named Joshua Giddings from Ohio. And when he first gets to Congress, he reports something like, “Our northern friends are afraid.” They’re afraid to stand up against the southerners. So there’s clearly evidence that people were afraid to stand up.

And not only does it shape the direction of debate, the people who do that kind of threatening very often are wildly supported by the folks back home. I suppose that’s what we’re going to see now; the person who does that kind of bullying and that kind of threatening gets a good degree of support for it.

Although Gosar was censured and stripped of his committee assignments, he was also somewhat rewarded for his behavior. Donald Trump immediately offered Gosar his endorsement, and the minority leader, Kevin McCarthy, suggested that he might get “better committee assignments” when Republicans regain control of the House. Is there a history of lawmakers being rewarded for violence?

Unfortunately, yes. Most notoriously, look at Preston Brooks, who caned Charles Sumner, and Laurence Keitt, who held people off from intervening in the caning. There was discussion of expelling Brooks. He does not get expelled, but he resigns in protest when the debate is attacking him for what he did. He resigns in protest and is immediately re-elected. And Laurence Keitt, who actually is censured, is immediately re-elected. So sometimes these violent acts are done partly for the base, for constituents, for “the cause”. And sometimes that is indeed rewarded.

So historically, have censures been effective in changing lawmakers’ behavior? Or do they sometimes encourage more of that same behavior?

On the one hand, you could say people are proving that they’re willing to stand up for something, and for some populations, that gets applause. But the thing is, if people are really being offensive in some way or another, and they’re not called on it … that’s basically an endorsement. And it’s also a sign that the rules of Congress almost don’t exist. They’re just not in play.

For reasons of just upholding that there are lines that can be crossed, I think it’s important for that to happen. The message of that kind of censuring is that this person did this thing and is accountable for that. And if you don’t hold people accountable for their actions, that too is a passive stab at democracy.

How did the violence in Congress before the civil war both reflect and intensify the divisions in the country itself?

The violence in Congress reflects and affects the violence and politics throughout the nation at large in a few ways. By the time you get into the 1850s and you have the telegraph, which is spreading that kind of information very quickly around the nation more broadly than ever before, Americans can see that happening. So that sets a tone for politics all by itself.

Some of it is playing to an audience. Depending on how it’s acted out and the language that’s used and the posturing that’s taken by the members of Congress, it’s deliberately intended to rile up Americans, which it does. That kind of violence can encourage violence, intensify political rhetoric [and] seemingly justify extremism and violence. It has an impact on the public.

If the public gets riled up, they’re going to demand more things from their representatives – more violence, more extremism.

Given everything you know about the congressional violence that happened leading up the civil war, what do you think the censure of Gosar says about the direction of our country now?

It certainly reflects the tone and tenor of our politics right now, and that almost goes without saying. It gestures towards what’s coming next because he’s going to be rewarded for it in some ways, and because of that, there will be others that follow in that model.

It also shows a certain lack of respect for the institution of Congress. The censure doesn’t matter clearly to this person. It’s a moment that shows how far party is above government and above institutions of government and above institutional stability. That’s not a very comforting thing to consider either.

We’re in very unpredictable times. We never know from one moment to the next what direction things are going to lean towards. It’s tempting to see an incident like [the Gosar censure] and assume from it we’re doomed. We’re in a moment of extreme contingency, and indeed things might become much worse.

But during that kind of moment of extreme contingency where anything can happen, those are also moments where it’s possible to make positive change. It’s possible in a moment of instability to really push for some kind of a change that isn’t necessarily in the direction of force and violence, but is rather in a direction of inclusion and rights. I think we as Americans need to be thinking about that right about now.