Watch: Democrat won't apologize for 'back of the bus' comment implying Republicans are racist

A top Senate Democrat refused to apologize on Thursday for saying Republicans are making the first black female nominee to be the nation's attorney general "sit in the back of the bus" by delaying her confirmation vote.

Senate Minority Whip Dick Durbin (D-Ill.) made the racially charged comment on Wednesday on the Senate floor to protest the delays that Attorney General nominee Loretta Lynch has faced.

"Loretta Lynch, the first African-American woman nominated to be attorney general, is asked to sit in the back of the bus when it comes to the Senate calendar," Durbin said. "That is unfair. It's unjust. It is beneath the decorum and dignity of the United States Senate."

His comment seemed to imply that Republicans are opposed to Lynch because she is black. What's more, the comment seemed to have approval from Senate Minority Leader Harry Reid (D-Nev.), who gave a staffer a knowing nudge just after Durbin delivered the line.

Thursday morning, Sen. John McCain (R-Ariz.) went to the Senate floor to demand an apology.

"What is beneath the decorum and dignity of the United States Senate … is for him to come to this floor and use that imagery, and suggest that racist tactics are being employed to delay Ms. Lynch's confirmation vote," McCain said.

McCain said that Durbin himself has voted against black women nominated by Republicans, but that he would never accuse Durbin of voting this way because of the nominee's race. "He should extend that same courtesy to me and my colleagues," McCain said.

"It was offensive and unnecessary, and I think he owes this body, Ms. Lynch and all Americans an apology," McCain concluded.

But Durbin, who spoke immediately afterwards, refused to apologize and ignored McCain's central complaint. Instead, he reiterated his argument that Lynch is qualified and that there is no good reason not to give her a vote.

"I'm not going use any pejorative terms, other than to say I believe it's insensitive for the Senate to hold her up for such a lengthy period of time," he said.

Republicans have said Democrats agreed to delay Lynch's confirmation vote to this year, and that it took time to organize the new Senate Judiciary Committee, one that's now under GOP control. Several snow days canceled some work days, and some Republicans wanted more time to ask her questions about how Lynch would serve as attorney general.

Republicans have also used Lynch's nomination in an effort to force Democrats to approve a human trafficking bill that has some anti-abortion language in it. Democrats have refused to allow any bill to advance this year in the Senate until they agree with it, and many conservatives say the GOP needs to use President Barack Obama's nominees as leverage in the ongoing legislative fight.