Iowa launched Bernie Sanders in 2016 and changed the rules in 2020: Documentary

In the 2016 Iowa caucuses, Sen. Bernie Sanders I-Vt., shocked many in the media and the Democratic establishment by coming within tenths of a percentage point of upsetting former Secretary of State Hillary Clinton.

"Nobody was more surprised by the rise of Bernie Sanders than Bernie Sanders," said Rachel Paine Caufield, author of "Iowa Caucus" in Fox Nation's new docuseries, "Proving Grounds: Iowa."

When the final results were announced, Clinton had bested Sanders by three-tenths of a percentage point, walking away from the caucuses with 23 delegates pledged to support her in the national convention compared to Sanders' 21.

"I think he got into the race to really make a point and to shape the issues and the agenda of the Democratic Party. And it took off," Paine told Fox Nation.

The close contest also exacerbated simmering tensions between the two camps that continue today and resulted in the Iowa Democratic Party changing the way it conducts its elections.

"Proving Grounds: Iowa," narrated by Fox News senior political analyst Brit Hume, did a deep dive into the history of the Iowa caucuses and how the 'first in the nation' caucuses have launched and stalled presidential campaigns.

"[Sanders] hit all the liberal buttons... that Iowa Democrats like to have pushed," said former Associated Press reporter Mike Glover. "And he managed to push all of them to put him into a virtual tie."

"Hillary won, but only by 0.3 percent. It was the closest race ever between two candidates in Iowa," narrated Hume.

The slim margin and the quirks of the Iowa caucus system raised questions over the results.

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"It is entirely possible that in a number of precincts, the number of people who supported Hillary Clinton and the number of people who supported Bernie Sanders were the same," said Paine. "And so somebody flipped a coin to determine who would get an extra delegate."

Sanders' supporters challenged the final count in 2016, but state officials found themselves at a loss when they tried to recreate the results.

The caucus system is significantly more complicated than a primary because caucus-goers engage in multiple rounds of voting.

They are first instructed to divide into groups based on their preferred candidates.  Then any group, whose number of participants fall short of a 15 percent threshold of the entire gathering, are asked to join other larger groups. Once all the groups meet the established threshold, the amount of support for each specific candidate is determined.

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Now, for the first time, the Iowa Democratic party will release the result of the first and second round of caucus voting, as well as the final tally.

"This year, we're going to have a clearer picture on caucus night. Or so they say," Fox News politics editor Chris Stirewalt told Fox Nation.

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

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