How does Ted Cruz’s RNC speech rank in convention mayhem? We asked an American historian.

“Cruz’s remarks were a striking rebuke of the nominee and can only be viewed as a major embarrassment for Trump,” wrote Vox’s Andrew Prokop about the high drama at the Republican National Convention. “And it will be the biggest story of this night of the convention.”

So just how unusual was Cruz’s speech? To get a sense of the strangeness of a major convention speaker implicitly blasting the party’s nominee, I emailed a few questions to Joshua Zeitz, a historian who has taught at Harvard and Princeton and written widely about conventions and party politics, late Wednesday night. This transcript has been lightly edited for length and clarity.

Jeff Stein: Can you put what happened tonight with Cruz’s speech in a historical context? How often have major convention speakers so clearly shown that they’re not behind the nominee in the past?

Joshua Zeitz: It’s not unprecedented, but it’s certainly rare.

In 1964, Nelson Rockefeller, the governor of New York, delivered a rousing speech before the Republican National Convention in San Francisco in which he denounced “the extremist threat, its danger to the party, and its danger to the nation” — meaning right-wing hate groups including the John Birch Society and Ku Klux Klan.

It was a clear shot against Sen. Barry Goldwater, the conservative candidate who had defeated him for the nomination and whom he was not endorsing. Right-wing delegates jeered as a defiant Rockefeller stared them down. One delegate recalled that “the venom of the booing and the hatred in people’s eyes was really quite stunning,” and one of Rockefeller’s fellow New Yorkers “felt like I was in Nazi Germany.”

But that’s where the comparison between Cruz and Rockefeller ends.

Rockefeller was the widely recognized leader of the liberal/moderate faction of the Republican Party. Like many other moderate Republicans, he was a stalwart supporter of civil rights legislation, anti-poverty measures, and an expansion of the social safety net. His wing of the GOP was much more aligned with liberal Democrats than with the Goldwater wing of the Republican Party, in the same way that most Southern Democrats at the time were more aligned with the Goldwater faction than with their own leadership.

What we saw tonight was Ted Cruz, a right-wing ideologue, being jeered by supporters of Donald Trump, a right-wing populist. The current debate is much more narrow and parochial.

JS: Is there anything that’s particularly leaped out at you as surprising about the discord on the convention floor?

JZ: Conventions used to be raucous affairs. In 1924, the Democrats took over 100 ballots to choose a nominee. They were deadlocked between Al Smith, the governor of New York, a Catholic who represented the rising urban, progressive wing of the party, and William McAdoo, a senator from California whose strength was concentrated with the party’s rural and Southern, more conservative, wing.

Supporters of McAdoo taunted Smith (an opponent of Prohibition) with cries of, “Booze! Booze! Booze!” Supporters of Smith replied with the taunt, “Ku Klux McAdoo!” Though McAdoo was no bigot, he drew the support of the Klan, which was then a major influence in politics.

Since the 1950s, when they were first televised, conventions have become highly scripted affairs. To be sure, we’ve seen some mayhem on the floor: the Republicans in 1964, the Democrats in 1968. But it’s been a while.

JS: You mentioned on Twitter that this is the worst-organized convention since the Democrats in 1972. What makes this convention so much worse?

JZ: Donald Trump revels in his anti-establishment credentials. But it takes an establishment to stage a successful convention. Half-empty bleachers, a lack of message (let alone message control), fumbles over Mrs. Trump’s speech, and an inability to control the coverage — it’s actually worse than the Democratic National Convention in 1972, which is saying a lot.

JS: Is this convention shorter on elected officials than any in the modern era — or any you’ve studied?

JZ: It’s certainly lighter on elected officials than any I’ve seen personally, and I’ve been watching these in rapt attention since age 6 (1980).

As a historian, I’m hard-pressed to think of a convention in modern history where so many of the party’s elected officials were missing. In 1972, quite a few moderate and conservative Democratic elected officials decided not to attend, in part out of opposition to George McGovern’s perceived radicalism. (It was unfair. McGovern was a man of the left but also a decorated combat veteran of World War II and accomplished legislator. History remembers him much more kindly than pundits in 1972.) But this is extraordinary.

JS: Has any convention in your knowledge ever leaned so heavily on the offspring of the presidential nominee?

JZ: Though Abraham Lincoln’s cousin famously appeared at the 1860 Illinois GOP convention carrying wood rails that the future president purportedly split as a young man, family member didn’t generally appear at nominating conventions until quite recently. In fact, most candidates only began appearing at conventions in the 1930s. Before then, they accepted their nomination from afar.

The practice of a nominee’s children speaking at the convention is relatively new. That said, Trump’s kids have done as fine a job as anyone who ever filled their shoes. Arguably, they’ve been the strongest speakers at the convention yet.

JS: What are some of the most awkward convention moments you’ve seen in history, and how do they compare to what we’ve seen tonight?
JZ: Well, there was the time that the Democrats were so badly divided between their Northern and Southern wings in 1860 that they adjourned, reconvened in another city, and then simply split in two and ran different candidates in the general election. Or the time in 1948 that several Southern state delegations walked out of the Democratic convention and formed the States’ Rights Democratic Party, or Dixiecrats. So far, the 2016 GOP convention has done better than that. But there’s still one night to go.

JS: Does this convention show a more divided party than any other in the modern era? If so, which come close?

JZ: It depends what we regard as modern. The closest comparison may be the GOP in 1976, when it was unclear until the bitter end whether Ronald Reagan, a conservative former governor of California, would topple Gerald Ford, a relatively moderate incumbent president. But in modern times there hasn’t been a candidate as tempestuous and unpredictable as Trump — and we still have one more night to go.