The 2016 presidential race has ignited passions, attracted new voters, and surprised pundits at nearly every turn.

It’s the kind of election that “people will write about,” says Heather Cox Richardson, Boston College Boston College historian and author of To Make Men Free: A History of the Republican Party. “It’s an election when the country makes a sea change.”

Richardson says although this election season – and its candidates – may seem unprecedented, history has some clues about what is happening in the Republican Party.

The “Forgotten” Connections Between Taxation and Racial Politics

The ideals and platforms of the Republican and Democratic parties are quite different today than they were when the parties were created in the 19th century.

This realignment of the two parties makes people forget, says Richardson, that it was the Republican Party that created the first national tax in 1861 – not the Democratic Party, which is more closely associated with taxation today.

The Republican Party was the party of anti-slavery activists and modernists – most famously Abraham Lincoln – and after the Civil War, according to Richardson, they used money from the new income tax to help newly freed slaves make the transition to freedom.

“What happens is people who don’t like that Republican platform and don’t like African Americans make the connection between an activist government that uses taxes and helping black people,” says Richardson. “So that’s been in American life since the 1860s.”

He said ‘the filthy rich have someone to speak for them, and the dirt poor have someone to speak for them, but there’s nobody to speak for me’ – that is absolutely out of the 1880s!

Historical Parallels

As Donald Trump holds steady in the polls as the Republican frontrunner – despite the efforts of numerous party leaders to denounce him – cracks between the party establishment and the party’s voters have become more apparent.

Richardson says this situation mirrors another time the Republican Party was deeply fractured.

In 1884, the Republican establishment nominated Senator James Blaine of Maine, who was widely disliked and viewed as corrupt, to run for president. A large number of Republican voters, according to Richardson, “jumped ship” and voted for Democrat Grover Cleveland, who won the presidency.

The election of a rival shocked the Republicans into action, she says: “People within the party took a look at what was going on and felt that they had to reform the party and American society in general.”

There was a major realignment within the party that launched the political careers of Teddy Roosevelt – among others – and laid the foundation for an era of progressive politics.

The Donald Trump Effect

According to Richardson, the first step in bringing a fractured party back together is to illustrate to party leaders that they’re no longer in touch with their voters. “And Trump is certainly doing that in a major way.”

Richardson says that she was struck by something a Trump supporter said to her recently: “He said ‘the filthy rich have someone to speak for them, and the dirt poor have someone to speak for them, but there’s nobody to speak for me’ – that is absolutely out of the 1880s!”

“We love to think of ourselves as a calm, reasonable nation. But in fact, political strife and where that leads is not at all unusual in America; it’s rather more the norm than not.”

Trump is fascinating to watch from a historical perspective, she says, because he’s a “snapshot” of American politics today.

On one hand, according to Richardson, Trump is addressing people – mainly white – “who have heard a storyline since at least 1980 that taxes only help people of color and women – marginalized people in society.” At the same time, says Richardson, Trump is picking up on a kind of economic, populist anger.

“He’s a snapshot of both the old ideology and the new reality.”

And what makes him even more interesting is that his language is more more like a salesman's than a politician's, she says: “He speaks in very short sentences, very simple words, and the final word of each sentence is a very dramatic noun – terror, fear. It’s to hit peoples’ emotions, just like salesmen do.”

Massachusetts Moderates

Former Massachusetts Governor and presidential nominee Mitt Romney, as well as current Governor Charlie Baker, are two prominent Republican politicians who have denounced Donald Trump.

Historically, Massachusetts is a fairly moderate state, and both Romney and Baker are a reflection of that, according to Richardson. She says Baker, who enjoys soaring approval ratings and has a history of bipartisanship, could be a future presidential candidate: “I think that Baker is very well set up to be the next voice of Republican moderation.”

“A Long, Hot, and Rocky Summer” Ahead

As tensions rise on the campaign trail – and within the Republican Party – Richardson is concerned about what that means for the Republican National Convention in Cleveland and the general election.

“We love to think of ourselves as a calm, reasonable nation. But in fact, political strife and where that leads is not at all unusual in America; it’s rather more the norm than not.”

The nature of Trump's promises on the campaign trail and the fervent nature of his supporters means that things could reach a boiling point, Richardson says: “He is simply not going to be able to deliver what he has promised, under any circumstances, because of the American system….and those people have nowhere to put their anger but outward.”

You can listen to the extended interview with WGBH's Henry Santoro and Boston College historian Heather Cox Richardson at the top of the page.