Even before Donald Trump became president, thoughtful Americans wondered how our politics had grown so partisan, irrational, and vengeful -- exemplified by Senate Republican leader Mitch McConnell's 2009 declaration that his principle objective would be to prevent the re-election of Barack Obama. With the advent of Trump and his hostile takeover of the Republican Party, those questions seem all the more urgent. Today, we excerpt the introduction to Burning Down The House: Newt Gingrich, the Fall of a Speaker, and the Rise of a New Republican Party -- a new book by the perceptive Princeton historian and CNN analyst Julian Zelizer that looks deep into the roots of our present predicament.

On the evening of July 13, 2016, the former Speaker of the House Newt Gingrich marched through the hallways of an Indianapolis television studio as he prepared to appear live on Fox News.

The past 24 hours had been a whirlwind. The Republican presidential nominee, Donald Trump, was seriously considering naming Gingrich his vice presidential running mate. Gingrich loved being back in the spotlight; to him, the thrill of politics was like a narcotic.

Suddenly Gingrich had a chance to return to the heights of power he had missed since his Republican colleagues had pressured him to step down as Speaker of the House, one of the most influential positions in Washington, back in November 1998. His downfall had been sudden, amid the climactic days of President Bill Clinton's impeachment, only four years after Gingrich had led the Republicans to take control of the House of Representatives for the first time since 1954. Following his dramatic departure from Congress, Gingrich experienced many professional ups and downs. The best of times came when he offered commentary on Fox News or filled the role of resident policy wonk at the conservative Heritage Foundation. He also enjoyed earning money as a consultant. But his disappointment was palpable when his 2012 bid for the Republican presidential nomination fell flat, bested by the former Massachusetts governor Mitt Romney, the smooth patrician to Gingrich's feisty populist.

But now Donald Trump might be offering Gingrich, who turned 73 that June, one last chance to step back into the center of power. Many experts argued that Gingrich had a pretty good shot at winning the vice presidential sweepstakes. His sexual past paled in comparison to the exploits of "The Donald" during his adventurous years in New York City. Gingrich was also one of the few senior figures in the Republican Party whom Trump had not knocked to his knees. The former Speaker exuded the kind of gravitas that the reality TV star lacked, displaying an easy fluency in public policy and foreign affairs. He also had an instinct for partisan warfare unequaled by almost any Republican besides Trump.

Moreover, Gingrich's competitors were flawed. The New Jersey governor, Chris Christie, had been damaged by a scandal about a manufactured traffic jam back in the Garden State. The Alabama senator Jeff Sessions seemed so much like a hard-line southern reactionary that he would instantly kill any hope that Trump could win over northern and midwestern independents. And the Indiana governor, Mike Pence, with his choirboy demeanor, felt much too boring a pick for the former star of The Apprentice, with his appetite for sensation and sizzle.

Gingrich was to be interviewed that night by Sean Hannity, the pugnacious Fox host whose tough-guy persona attracted a passionate right- wing audience. The day of the Fox interview, Trump had met with Gingrich in a 2000 square-foot penthouse suite at the Conrad hotel, a posh five-star high-rise in downtown Indianapolis. Trump had intended to fly back to New York the previous evening after attending a rally with Governor Pence, but a flat tire on the airplane had grounded him overnight. Hannity, a close friend and ally of both Trump and Gingrich, had secretly allowed the former Speaker to fly on his private jet to Indianapolis to make sure that their scheduled meeting took place.

For about two and a half hours, Trump's campaign chairman Paul Manafort, son-in-law Jared Kushner, and children Eric, Donald Jr., and Ivanka sat in as the presumptive Republican nominee and the former Speaker held a free-flowing conversation about the role of the vice president, relations with Capitol Hill, and the many issues facing America after Barack Obama's presidency. Gingrich found Trump exhilarating, a fresh voice who would not be muted by the ostensible experts. The last great Republican firebrand saw the new one as a kindred spirit, one who shared Gingrich's ruthless and defiant attitude toward political convention and his mastery of the media.

That night Gingrich strode through the usually sleepy local studio; all the campaign activity had amped up the station's energy level, but having Gingrich on-site created a pronounced buzz. He was one of the rare former members of Congress who was recognized on the streets. Walking through the studios, Gingrich looked to some on the newsroom staff more like the overweight college professor he had been in his early years, lost in his own thoughts, than someone who might soon be next in line for the presidency. Although he was wearing the classic outfit of the Washington male politician—a dark suit with a royal blue shirt and a red power tie—Gingrich didn't have the normal polish. His suit was a little too boxy; its occupant was slightly rumpled.

Gingrich didn't care: this was the look that he had nurtured since entering politics 37 years earlier as a young congressman from Georgia. He liked that his colleagues thought of him as the man with the big ideas, the intellectual turned politician. He had used that image to intimidate his opponents into submission, whatever the issue being debated. It was rare that Gingrich, with his trademark smirk, didn't seem to think that he was 100 percent correct about the topic being discussed. While he looked as if he might fit naturally in a seminar room, deep down Gingrich had the take-no-prisoners mentality of the toughest partisan figures who had ever served on Capitol Hill. He had practically written the handbook on cutthroat congressional tactics and spinning the media for partisan advantage; indeed, during his speakership, conservatives had literally circulated a memo on how to "speak like Newt."

As the makeup artist finished powdering his face and the production crew attached a small microphone to his lapel, Gingrich had good reason to feel that Trump would never have become the nominee without him. It wasn't just that Gingrich had been a loyal supporter throughout the primaries but also that the unlikely, unorthodox, nativist populist campaign Trump had mounted, which aimed to tear down the political leaders of both parties and to destabilize the entire U.S. political system, was Gingrich's creation. Trump's media-centered strategy and his determination to capitalize on public distrust of Washington were the same weapons that Gingrich had deployed upon his arrival on Capitol Hill, when he went after the Democratic majority in the 1980s.

Like Trump, Gingrich believed that anything was possible in politics. He hated it when colleagues told him that things were always going to be the way they were—especially when they said that Republicans would always be the country's minority party. When Ronald Reagan was president from 1981 to 1989, Gingrich had worked diligently as a backbencher to remake the Republican Party's then-staid, country-club, business-oriented brand into something far more hard hitting and confrontational. He committed himself to being a foot soldier in the Reagan Revolution. His goal: shove the national policy agenda to the right and wrest power away from the Democrats who had controlled the House for three decades. To almost everyone, it was a pipe dream.

But Gingrich came to the House in 1979 from a Georgia district that had been reliably Democratic for generations. He had won, and so could others in his party if they played by new rules, which he himself would invent. Gingrich promoted a style of smashmouth combat aimed at delegitimizing his opponents by whatever means possible. Politics, as he saw it, was like warfare. The only way to win a battle, he decided, was to unleash the full fury of one's firepower on the foe. Now Trump was using the same approach on his way to the presidency.

The camera light flashed on in the Indianapolis newsroom, and the interview began. Listening to Hannity's voice through his earpiece, Gingrich jumped into the discussion with verve. As the Fox anchor offered the Georgian friendly questions about his meeting with Trump and his vice presidential prospects, Gingrich turned up the wattage. Speaking in his familiar professorial style, Gingrich launched a fusillade of persuasion, listing the obvious similarities between himself and Trump that would make them ideal partners: "I'm an outsider, I'm oriented toward moving the great base of the party, communicating big ideas, being on television." Gingrich paused to mutter that he probably shouldn't say what he was thinking aloud, then connected the dots between his own congressional career and Trump's presidential campaign: "Look, in many ways, Donald Trump is like a pirate. He's outside the normal system, he gets things done, he's bold, he's actually like a figure out of a movie. In a lot of ways, my entire career has been a little bit like a pirate. I've taken on the establishment of both parties, [I'm] very prepared to fight in the media."

Then Gingrich took the conversation with Hannity in an unexpected direction. As much as he wanted the job, Gingrich said, he could not resist pointing out why he might not be the best selection. Displaying his trademark audacity, on the eve of this historic decision, he pointed Trump toward Gingrich's second choice: Mike Pence. Trump would have to decide whether he wanted a "two-pirate ticket," Gingrich said. If Trump didn't want to run with such a like-minded person, Pence might be better as a stabilizing force. This admission appeared to take Hannity by surprise, but it was classic Gingrich: He had always tended to say exactly what was on his mind, for better or worse.

After the interview ended and the crew removed his mic, Gingrich walked out of the studio. Whatever the next few days brought, he could feel as though he had won. Trump was thriving in the political world that Gingrich had created. Gingrich would always be Michelangelo to Trump's David.

In Gingrich's world, Republicans practiced a ruthless style of partisanship that ignored the conventional norms of Washington and continually tested how far politicians could go in bending government institutions to suit their partisan purposes. Republicans went for the head wound, as Trump's adviser Steve Bannon said, when Democrats were having pillow fights. The new GOP goal was not to negotiate or legislate but to do everything necessary to maintain partisan power. If it was politically useful to engage in behavior that could destroy the possibility of governance, which rendered bipartisanship impossible and would unfairly decimate their opponents' reputations, then so be it. Gingrich-era Republicans were willing to enter into alliances of convenience with extremists who trafficked in reactionary populism, nativism, and racial backlash. The party kept counting on Gingrich's media-centered strategy, tailoring its actions and statements to push the national conversation in its favor, even if that depended on mixing fact and fiction and practicing a new, brass-knuckles politics of smear.

The style of partisanship that Gingrich popularized supplanted the bipartisan norms of the committee era of Congress (1930s–1960s) as well as the responsible partisanship that had been promoted as an alternative by Watergate-era reformers (1970s), when leaders and the rank and file were loyal to their party agenda while still adhering to formal and informal rules of governance. Gingrich's approach to partisanship was an entirely different beast. Nothing and nobody was sacrosanct.

To be sure, this was not the first time in American history that conditions on Capitol Hill bottomed out. Congress had been through numerous periods of vicious partisanship, such as the decades leading up to the Civil War, when relations disintegrated so badly that bloody altercations on the floors of the House and the Senate were regular occurrences until the government broke down into total dysfunction. While Gingrich's era of partisanship did not witness outright physical violence between members, what did take root was the normalization of a no-holds-barred style of partisan warfare where the career of every politician was seen as expendable and where it was fair game to shatter routine legislative processes in pursuit of power, even when there was not an issue as monumental as slavery on the table. In Gingrich's era, a crippling form of partisanship came to permanently define how elected officials dealt with almost every issue, ranging from who should lead the parties to mundane budgeting matters to decisions over war and peace.

From the book BURNING DOWN THE HOUSEby Julian Zelizer, by Penguin Press, an imprint of Penguin Publishing Group, a division of Penguin Random House LLC. Copyright © 2020 by Julian Zelizer.

Julian E. Zelizer is the Malcolm Stevenson Forbes, Class of 1941 Professor of History and Public Affairs at Princeton University and a CNN Political Analyst. His most recent books are Fault Lines: A History of the United States Since 1974 (co-authored with Kevin Kruse) and The Fierce Urgency of Now: Lyndon Johnson, Congress, and the Battle for the Great Society, the winner of the D.B. Hardeman Prize for Best Book on Congress. Zelizer has been awarded fellowships from the New York Historical Society, the Russell Sage Foundation, the Guggenheim Foundation, and New America.