WASHINGTON —  The second-ranking Senate Democrat on Wednesday accused Republicans of putting the president’s attorney general nominee “in the back of the bus’’ by delaying her confirmation.

Sen. Dick Durbin of Illinois made the comment on the Senate floor as he criticized the GOP over its handling of Loretta Lynch’s nomination. She would become the nation’s first black female attorney general, replacing Eric Holder, the first African-American in the job.

Lynch was nominated last fall and Democrats are growing increasingly agitated over the holdup in confirming her, although they were in control of the Senate for some of that time.

“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.’’

Senate Majority Leader Mitch McConnell planned a vote on Lynch’s nomination this week but delayed it when the Senate was unable to finish work on a bill to combat human trafficking. That legislation is stalled because of a partisan spat over abortion funding, with Democrats objecting to a provision blocking money in a new victims’ fund from paying for abortions in most cases.

“The Lynch nomination is next on the schedule. The only thing holding up that vote is the Democrats’ filibuster of a bill that would help prevent kids from being sold into sex slavery,’’ McConnell spokesman Don Stewart said in response to Durbin. “The sooner they allow the Senate to pass that bipartisan bill, the sooner the Senate can move to the Lynch nomination.’’

Democrats claim Republicans snuck the abortion provision into the trafficking bill without telling them. Republicans note that the language has been there since the bill was introduced early this year, and no one raised objections as it unanimously passed the Judiciary Committee. Democrats insist they weren’t aware of it.

It’s not clear how the issue will be resolved. Both sides say they want to get the bill passed, but Democrats are milking the politics of the dispute. Around the same time Durbin made his racially charged accusation on the Senate floor, female senators held a press conference with women’s groups to accuse Republicans of a “war on women.’’

A procedural vote to move ahead on the trafficking measure failed Tuesday when Democrats blocked it, and a similar motion was expected to fail later Wednesday.