"There was a promise that they were going to treat her with respect," Sen. Dick Durbin, D-Ill., said at a news conference Wednesday night, "obviously four or five of those colleagues didn't get the memo."
He didn't name specific senators.
Durbin, the chairman of the Senate Judiciary Committee, said Jackson showed an "amazing display of grace and dignity and strength" in the face of questioning from some GOP senators "who were just vicious in their attacks."
Sen. Sheldon Whitehouse, D-R.I., decried the behavior of some Senate Republicans as "truly poisonous, cynical behavior that trolled through the absolute bottom of what the Senate has done in dark times past."
Sen. Richard Blumenthal, D-Conn., said Jackson appeared even "more dignified and even majestic" in the face of "shameful, really disgraceful" behavior from Republicans over two long days of questioning. Sen. Jon Ossoff, D-Ga., described the attacks as "cruel and unfair."
Several Republicans on the Judiciary Committee repeatedly peppered Jackson with questions about her sentencing of child porn offenders as a federal court judge and implied she was too lenient on criminals when her sentences were less than what prosecutors and sentencing guidelines recommended.
"All I can say is that your view of how to deter child pornography is not my view," Sen. Lindsey Graham, R-S.C. told Jackson. "I think you're doing it wrong. And every judge who does what you're doing is making it easier for the children to be exploited."
The exchanges with Graham, and GOP Sens. Josh Hawley of Missouri and Ted Cruz of Texas were especially contentious.
Durbin, at times, intervened, chiding senators for interrupting Jackson and not giving her an opportunity to talk. At one point, Durbin tried to gavel the hearing to order after Cruz went over his allotted time as he tried to solicit an answer from Jackson on a child porn sentencing case.
Republicans, however, say it was Democrats with the record of demonizing nominees and their treatment of Jackson was nothing in comparison to how Democrats vilified conservative nominees, especially Justice Brett Kavanaugh.
Cruz told "Jesse Watters Primetime" the same Democrats often went "into the gutter" in their questioning of then-nominees Kavanaugh and Amy Coney Barrett — adding that GOP questions of Jackson were relevant to her record, not personal.
"You played clips of the Democrats slamming Republican nominees, going personal, going into the gutter, going after their character," Cruz said Wednesday night. "If you look at the hearing the last two days, the questions that Republicans focused on were her record and in particular, her judicial record."
Despite the tensions at the hearing, Democrats were optimistic that Jackson would be confirmed to the court and make history as the first Black female justice.
"She is an inspiration to all of us," a visibly emotional Sen. Pat Leahy, D-Vt., said at the news conference, "to our families, to those of us who have daughters and granddaughters – both white and Black."
He compared the treatment Jackson faced to the "era of Jim Crow."
"She will be confirmed," Leahy said. "She'll be a star of the Supreme Court."
Fox News' Charles Creitz contributed to this report.