WATCH: Plagiarized speech that sank Biden's 1988 presidential campaign

With four days to go until the Iowa Caucuses, former vice president Joe Biden’s campaign released a new political ad called "Character" that will air in Iowa's top five markets. 

However, it was in Iowa in 1987 that then-Sen. Biden delivered a plagiarized speech that led him to abandon his first presidential campaign.

In Fox Nation's new docuseries, "Proving Grounds: Iowa," Fox News senior political analyst Brit Hume recounts the history of the Iowa caucuses, how they came to be the first contest in the primaries, and detailed the presidential campaigns that the state launched and abruptly ended.

"Joe Biden, a senator from Delaware... closed the debate at the Iowa State Fair with an emotional invocation of his coal-mining ancestors," narrated Hume in the Fox Nation show. "The rival [Michael] Dukakis campaign leaked a tape proving Biden had plagiarized the bit from a speech by a British politician talking about his family."

"I started thinking as I was coming over here, why is it that Joe Biden is the first in his family ever to go to a university?" said Biden in Iowa in August 1987.

"Why is it that my wife who is sitting out there in the audience is the first in her family to ever go to college?" he continued, gesturing to his wife Jill. "Is it because our fathers and mothers were not bright?"

"My ancestors, who worked in the coal mines in northeast Pennsylvania, who would come up after 12 hours and play football for four hours," he went on, arguing that he is fighting to help struggling Americans. "It's because they didn't have a platform upon which to stand.''

The words and phrases mirrored -- almost exactly -- the campaign speech of British Labor Party leader Neil Kinnock.

In his remarks, Kinnock said, "Why am I the first Kinnock in a thousand generations to be able to get to university?"

"Why is Glenys the first woman in her family in a thousand generations to be able to get to university?" he said referencing his own wife.

"Was it because all our predecessors were thick?... Those people who could work eight hours underground and then come up and play football?"

"It was because there was no platform upon which they could stand," Kinnock concluded.

It ultimately sank Biden's presidential ambitions that year.

"When more instances of plagiarism followed, Biden withdrew," narrated Hume.

JUSTICE CLARENCE THOMAS: JOE BIDEN HAD 'NO IDEA' WHAT HE WAS TALKING ABOUT AT CONFIRMATION HEARINGS

The Delaware senator also admitted to being accused of plagiarism in law school and was shown to have padded his academic record while speaking to voters in New Hampshire.

"I'm angry with myself for having... put myself in the position of having to make this choice," said Biden at a Sept. 23, 1987, news conference that he called to announced his decision to drop out of the race. "And I am no less frustrated for the environment of presidential politics."

In the Biden campaign ad released on Thursday, a narrator reads over images of the Oval Office, "It’s said that in here, your character is revealed," the spot concluded. "Character matters, maybe more here than anywhere."

"Proving Grounds: Iowa" is available exclusively on Fox Nation.

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