Michael Eric Dyson, a professor of sociology at Georgetown University, on Tuesday called Sen. Cindy Hyde-Smith (R., Miss.) a racist and a white supremacist.

"Cindy Hyde-Smith is a racist, a white nationalist, a white supremacist, and it is a shame that white Mississippians would exonerate her in advance and excuse her for the intimidating hatred that she expresses," Dyson said on MSNBC. "And God forbid that she would therefore be elected to go to the Senate of the United States to do more damage to Mississippians and America in general."

Neither Ali Velshi nor Stephanie Ruhle, the MSNBC hosts interviewing Dyson, pushed back on the professor's claims. Instead, Ruhle turned to another guest and asked, "Do we understand white Mississippians?"

Hyde-Smith, who was appointed to the Senate after Sen. Thad Cochran (R., Miss.) resigned for health reasons in April, is hoping to hold her seat in Mississippi's special run-off election on Tuesday against Democrat Mike Espy.

Hyde-Smith has received criticism for a comment she made earlier this month praising a cattle rancher by saying, "If he invited me to a public hanging, I'd be on the front row."

Espy, an African American, and other Democrats castigated the remark, noting Mississippi's history of lynchings. Hyde-Smith apologized for the comment and said she meant nothing racial.

"I never intended any ill will toward anyone with any of my comments," she said. "It was never there. My comments were taken and twisted and used as a political weapon against me by my opponent, and that is just wrong."

Earlier on Tuesday, former Democratic Congressional Campaign Committee spokesman Doug Thornell falsely claimed on MSNBC that Hyde-Smith had said she would attend a "public lynching." He did not receive pushback from the host, Craig Melvin.