Kurt Bardella, who worked with Bannon at Breitbart for two years, says the former Breitbart News chairman regularly disparaged minorities, women, and immigrants during daily editorial calls at the publication.
ABC News reached out to Bannon for comment but did not receive a response.
“If anyone sat there and listened to that call, you’d think that you were attending a white supremacist rally,” said Bardella, citing what he called Bannon’s “nationalism and hatred for immigrants, people coming into this country to try to get a better life for themselves.”
“This is someone who has a very low moral compass,” he said of Bannon, “and the idea that this is the type of person that Donald Trump, as the Republican nominee, as president, would have closest to him is very disturbing.”
Bardella joined this week’s episode of “Powerhouse Politics” podcast with ABC News Chief White House Correspondent Jonathan Karl and ABC News Deputy Political Director Shushannah Walshe to discuss the recent shakeup in the Trump campaign.
Asked how he thinks Bannon's hiring will affect the Trump campaign, Bardella said: “It’s going to look like exactly what it’s looked like to this point.”
“Chaos, undisciplined, a lot of attacks, negativity," Bardella said. "There is no vision for moving this country forward. It’s just a portrait of negativity and ugliness and pitting people against one another, and using coded language to try to send certain hints to the very core constituencies.”
“A big reason why I decided that Hillary Clinton is the candidate who I’m voting for -- the first Democrat I’m voting for in my life -- is because this is a time where what’s going on is much bigger than partisanship, bigger than Republican or Democrat, or single issues that traditionally these campaigns are about,” Bardella said.
“This is about what this country will look like four years from now,” he continued. “Four years from now, under a Trump administration, your guess is as good as mine what it could look like, but it could look very, very bad, potentially catastrophic.”
In contrast to Bardella, a conservative who remains a strong Trump backer is political consultant Roger Stone, a self-described “F.O.T.” or “Friend of Trump,” who also joined the “Powerhouse Politics” podcast this week.
“This is not a shakeup, this is an expansion. These are people joining the team,” Stone said. “It’s not a demotion in any way.”
Stone saw Bannon’s hiring as a major positive addition to the Trump campaign, explaining that the former Breitbart chairman’s knowledge of new media could help Trump reach young voters who don’t watch cable television.
“I have a very high regard for Stephen Bannon,” Stone added. “He understands the new media, and that has been lacking I think. Other than the notable success of Trump’s own Twitter feed, which is pretty amazing.”
“Beyond that, the Clintonites have done a much better job in the new media, on the net and so on, so I think Bannon brings that knowledge because digital is where it’s at.”Asked whether Bannon will change the direction of the campaign, Stone said: “There is only one person who decides what Trump says and does, and that’s Trump.”
“Having worked for him on and off for almost 40 years, he is unscripted, he is unprogrammed, he is uncoached," Stone said. "He speaks from the heart.”
But Stone, who says Trump has “maybe a 4 in 10, closer to 5 in 10” chance of winning, had some advice for the Republican nominee.
“I think it’s important that Donald stay on message on the core reasons that got him nominated: immigration, trade, our fiscal situation, and so on,” said Stone. “I think everyone in the campaign realizes that if this election is about Trump, it will be harder to win. This election has to be about the incumbent party, which Hillary represents, and whether her candidacy would represent four more years of what we have now.”