CNN senior data reporter Harry Enten revealed on Tuesday that former President Donald Trump's running mate, Sen. JD Vance, R-Ohio, is the first vice presidential nominee to have a net negative favorability rating following his party's convention.

"I have gone all the way back since 1980. He is the first guy after, immediately following a convention, a VP pick, who actually had a net negative favorability rating that is underwater," Enten said.

He also said that the average net favorability rating for a VP nominee was plus 19 points since 2000.

"JD Vance, making history in the completely wrong way," Enten added.

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Senator JD Vance speaks during the Republican National Convention

Sen. JD Vance, a Republican from Ohio and Republican vice-presidential nominee, speaks during the Republican National Convention at the Fiserv Forum in Milwaukee on July 17. (Al Drago/Bloomberg via Getty Images)

While Vance hails from Ohio, a one-time battleground state the former president comfortably carried in the 2016 and 2020 elections, the senator's selection is expected to boost Trump among working-class Democrats, especially across the Rust Belt, who otherwise might have been supporters of President Biden, according to multiple experts who spoke with Fox News Digital as Trump was weighing his options.

Enten refuted the idea that Vance would help in the Rust Belt and Ohio, noting that Vance only obtained his home state senate seat by 6 points in 2022. In comparison, Trump claimed Ohio by 8 points in 2020 and Republican Gov. Mike DeWine handily won the state by 25 points nearly two years ago.

Vance was an early critic of Trump in 2016 when the former president was campaigning to beat Democratic presidential nominee Hillary Clinton.

At the time, Vance had dismissed Trump as "cultural heroin" who was leading the disenfranchised working class into a "very dark place."

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JD Vance polling CNN

JD Vance is the first vice presidential nominee to have a net negative favorability rating following his party's convention.  (CNN/Screenshot)

Vance's stance began to shift while Trump was in office, which the Ohio senator said proved many of his assumptions wrong.

"I was wrong about him," Vance told CNN in May. "I didn't think he was going to be a good president. And I was very, very proud to be proven wrong. It's one of the reasons why I'm working so hard to get him elected."

In a Monday interview with Fox News, Trump said that he and Vance had "automatic chemistry" and dismissed the pair's past disagreements as a misunderstanding.

"Originally, JD was probably not for me, but he didn't know me," Trump said in the "Jesse Watters Primetime" interview. "And then when we got to know each other, he liked me maybe more than anybody liked me."

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