The presence of “Trojan horse" delegates—or "double agent" delegates, as Donald Trump calls them—is not a new phenomenon at a Republican convention. There were many at the last convention during which a presidential nomination was contested.

That was in 1976. And guess what these delegates, pledged to one candidate but sympathetic to a rival, did? Not much. The delegates bound to President Gerald Ford but secretly in favor of Ronald Reagan didn't violate their pledge to vote for Ford on the first ballot. And Ford won.

But what was more revealing was the failure of a convention rule change that the Reagan forces figured would hurt Ford and catapult Reagan to the nomination. The change would have required Ford to name a vice presidential running mate—Reagan had already named one—before the vote on nominating a presidential candidate.

The Ford delegates who were pro-Reagan were free to vote for the change. Few did, but the exact number is unknown. How "these Reagan delegates in Ford clothing" voted was never recorded, Reagan biographer Craig Shirley wrote in his definitive account, Reagan's Revolution: The Untold Story of the Campaign That Started It All. Nor did they identify themselves publicly.

But there was another factor: Ford had his own Trojan horse delegates. "For example," Shirley wrote, "Indiana delegates were legally required to vote for Reagan on the first ballot, though most clearly favored Ford." In North Carolina, the opposite occurred. Reagan ally Tom Ellis took advantage of the opportunity to choose delegates. Ford had lost the primary but won delegates. Ellis installed Reaganites in all but two of the Ford slots.

In the end, all the maneuvering had minimal impact. Ford defeated the change, known as Rule 16-C, by 111 votes and won the nomination by 117 votes on the first ballot. That suggests the hullabaloo over the rule had a net effect of six votes.

If you're looking for a lesson for this year's GOP convention in the fight 40 years ago, there's not a big one. The closest thing is that rule challenges and other gimmicks by a candidate who is trailing usually don't work. They are often complicated and unique, with little or no relevance to later conventions.

As a reporter for the Washington Evening Star, I covered the 1976 convention in Kansas City. In terms of excitement and drama, it hasn't been improved on. The Cleveland convention this July may surpass it if Donald Trump, the frontrunner for the nomination, falls short on the first ballot, Trojan horse delegates are unbound, and an "open" convention ensues. We'll see.

Trump talks about unifying the Republican party, but there is little chance of that if he's the nominee. Like the GOP itself, the convention will be divided and angry. This is a bad omen.

The last time Republicans were bitterly divided was in 1964 when conservative Barry Goldwater was nominated. Moderates and liberals abandoned Goldwater, and in the general election he lost to President Lyndon Johnson in a landslide.

"Divided conventions lead to losing in the fall," Shirley said in an interview. This happened with Democrats in 1968 and 1972 and, as Michael Barone has noted, in 1912 when Republican Theodore Roosevelt bolted and ran on the Bull Moose ticket. That split the Republican vote and Democrat Woodrow Wilson won the election.

In 1976, convention delegates were stars. The media paid enormous attention to them. They weren't just counted. They were interviewed at state delegation meetings and on the convention floor. This was a product of a contested convention with an uncertain outcome.

Since then, Republican consultants, campaign strategists, and party officials have been the media's focus. This was the product of conventions in which the presidential nomination had been decided months earlier. Why interview delegates when the result of their votes is already known to everyone?

In Cleveland, delegates should be important players again. Why interview a consultant when a Trump delegate whose real allegiance is to Ted Cruz is available? And unlike in 1976, most of the Trojan horse delegates will be known to reporters. If they held their own caucus, the media would swarm the event.

Forty years ago, the Mississippi delegation drew crowds of press, most of them newspaper reporters in those pre-Internet days. They found all the drama and tragedy they could have imagined as Mississippi anguished over whether to embrace Reagan or Ford.

The delegation was headed by Clarke Reed, the state chairman and an influential conservative in his own right. Reed knew Reagan and initially preferred him. But Ford and his agents continued to woo him, insisting a vote for Reagan would be wasted since Ford was ahead and more likely to win. Their argument worked. Reed flipped and Mississippi, operating under the unit rule, gave all its votes to Ford.

That episode points to a lesson that ought to please Trump: The candidate closest to having a majority of the delegates has the best chance of winning. That candidate can claim his train is leaving the station and you'd better get on. Reed did.

Jeffrey Bell was a Reagan adviser in 1976. He went to the trailer outside the convention hall where the floor operations were managed. When Reagan lost, "there wasn't a dry eye in that trailer," he says. "They were weeping, openly, dramatically. I'd never seen anything like that."

Maybe there will be sobbing in the loser's trailer in Cleveland. But after this brutal and nasty campaign, I doubt it.

Fred Barnes is an executive editor at The Weekly Standard .