"After a long and contentious campaign, it seemed to me that the President-elect implicitly acknowledged that some of the rhetoric used during the race had alienate and offended some of our communities," Franken said Thursday on the Senate floor, citing Trump's promise to be a "president for all Americans."
Franken said that he was "encouraged" by Trump's call for unity, but "disappointed" by news of Bannon's appointment to a position in the West Wing.
"The selection of Mr. Bannon to serve at the very highest level of our government does not signal a willingness to set aside our differences and embrace unity," Franken said. "Far from it."
He cited Bannon's position as chairman of Breitbart News, and said that the conservative news site "took a darker turn" under Bannon's leadership.
"Mr. Bannon guided Breitbart away from more mainstream conservative opinion to instead traffic in an ideology of racism, misogyny, xenophobia, homophobia, and anti-Semitism," Franken said.
He cited headlines published by the site including “Gabby Giffords: The Gun Control Movement's Human Shield" and "Hoist It High And Proud: The Confederate Flag Proclaims A Glorious Heritage," which was published two weeks after nine black parishioners died in a shooting at a Charleston, South Carolina church. The shooter, a white man, posted photos of himself with the Confederate flag.
"This is nasty stuff," Franken said. "This is vile, and it comes all the way from the top, from Mr. Bannon himself."
He acknowledged that extreme rhetoric became widespread over the course of Trump's campaign, but called on the President-elect to take a stand against such "dog-whistle politics."
"It is imperative that we not allow these corrosive tactics to become normalized," he said. "If President-elect Trump truly meant what he said during his victory speech, if he truly hopes to be president for all Americans, he will recognize that such tactics stand in the way of that goal. And he will renounce them."
Franken called on Trump to unify the country by addressing the "wounds" incurred over the course of the long presidential campaign.
"I urge President-elect Trump to begin that work by surrounding himself with people equal to the task," he said. "Mr. Bannon is not one of them. And he should not serve in the next administration."