GEOFF BENNETT: It has been a convention unlike any other, with the assassination attempt against former President Donald Trump lingering over the week.

But this moment is just the latest on the long timeline of the Republican Party.

AMNA NAWAZ: Our Lisa Desjardins is back now with a look at the birth of the GOP and what it means for today.

MANDY KIMES, Executive Director, Ripon Area Chamber Of Commerce: Did you hear about the birthplace of the Republican Party yet?

LISA DESJARDINS: Just outside the Republican National Convention in Milwaukee, Mandy Kimes is giving history lessons to anyone who will listen.

MANDY KIMES: It happened just an hour-and-a-half away from here.

It's 170 years old.

LISA DESJARDINS: She's traveled almost 100 miles from the small town of Ripon, Wisconsin, bringing a replica of the original little white schoolhouse where the Republican Party was born 170 years ago.

MANDY KIMES: I really think people are kind of surprised when they're learning about history.

And I think because this is the story of the Republican Party, we have kind of like a hook to draw them in.

And then all of a sudden, they're learning something even deeper than what they thought it was.

LISA DESJARDINS: But before my lesson, I asked Kimes about much more recent history, the attempted assassination of former President Trump.

MANDY KIMES: I think, if anything, it's made everything feel more poignant and more important.

But I think there's still a sense of camaraderie, a sense almost like pulling together and a united front.

There's definitely a thing of like, we are all one family here.

So this was obviously a schoolhouse.

And this was also a gathering place for the community.

LISA DESJARDINS: We first met Kimes before the convention at the real Little White School House in Ripon, where her enthusiasm is infectious.

MANDY KIMES: The fact that these ordinary people in this ordinary place actually got together and stood up against what they believed in and then changed the world is, like, cool.

Like, it's extraordinary.

LISA DESJARDINS: She's the head of the local Chamber of Commerce and leads tours at the schoolhouse.

MANDY KIMES: The threat of the expansion of slavery was an issue for many.

LISA DESJARDINS: It was here in 1854 that a new political party took shape around opposition to slavery.

MANDY KIMES: And so if slavery were allowed to move in, it would be an economic threat.

LISA DESJARDINS: The original building, which has moved multiple times, now sits in what could be an easy-to-miss spot on one of the town's main roads.

Once inside, visitors can find a host of artifacts, the words of party founders, and a space for conversations about political divides of today.

KEITH HELLWIG, Wisconsin Resident: Let's get back to what's best for our country, instead of what's best for the party.

Keith Hellwig and Rory Tompkins lived near the schoolhouse, but they'd never stopped to see it.

When they did, they found the history of 1854 still relevant today.

RORY TOMPKINS, Wisconsin Resident: I do feel the country is very divided.

Both sides, they're playing the people.

And I feel that, if they keep us divided, it keeps our focus off of what they're doing.

SAM ROSENFELD, Colgate University: The two eras that come to mind of the danger of political violence being at the level it is right now would be the 1850s, the kind of run-up to the Civil War, and the 1960s.

LISA DESJARDINS: Sam Rosenfeld is a political scientist at Colgate University who has studied polarization throughout U.S. history.

He says this moment has the nation on edge.

SAM ROSENFELD: The assumption that given the level of conflict and divisiveness in American politics right now, that kind of violent event could inevitably cascade into more political violence.

I don't think that particular assassination attempt is going to do so, but, yes, this is a period in which there is real danger of political violence, in part because of the rhetoric of major political actors in American politics right now.

MANDY KIMES: We really feel strongly that this is Ripon's history, and it's part of our, like, heritage as a city.

LISA DESJARDINS: Back outside the convention, Kimes keeps sharing this story.

MANDY KIMES: The thing I hope people will take away from this history is that we can find ways to work together and we can find ways to listen to one another.

And that's really what happened in that little schoolhouse so long ago.

LISA DESJARDINS: A small schoolhouse still giving big lessons.

For the PBS "News Hour," I'm Lisa Desjardins in Milwaukee.