President Obama will not nominate a new attorney general until after the midterm election, a White House official said Tuesday.

The White House decided to delay naming the replacement, partially at the request of Senate Democrats, according to a source familiar with the decision. The White House believes that waiting until after voters head to the polls will keep the nomination from becoming mired in election-year politics.

The administration had previously hinted that they hoped to hold a confirmation vote on a replacement for Eric HolderEric Himpton HolderHolder: 2018 vote crucial to combating gerrymandering Holder: Sessions needs to 'have the guts' to say no to Trump Holder urges Justice Dept, FBI officials to 'be strong' in face of attacks: 'It will get worse' MORE during the lame-duck session of Congress. Press secretary Josh Earnest has repeatedly noted that Defense Secretary Robert Gates was nominated and confirmed during the 2006 lame-duck session, and Attorney General Michael Mukasey was confirmed within seven weeks of his nomination by President George W. Bush.

"So, there is a precedent for presidents making important Cabinet nominations and counting on Congress to confirm them promptly, even in the context of a lame-duck session, if necessary," Earnest said.

But the decision to hold off on nominating a new attorney general might further complicate the administration's desire to get a nominee through in the lame duck, an effort that could become especially important if Democrats lose control of the Senate, as most election forecasts predict.

“This timing shows, once again, that the President and Democrat Senate leaders are willing to play politics with important policy decisions,” Sen. Chuck GrassleyCharles (Chuck) Ernest GrassleyGrassley on Trump calling Putin: 'I wouldn't have a conversation with a criminal' Lawmakers zero in on Zuckerberg GOP senator blocking Trump's Intel nominee MORE (R-Iowa), ranking member of the Judiciary Committee, said in a statement. “First it was immigration, and now Senate Democrats have asked the President to delay his announcement for Attorney General so they can avoid making clear to the voters of their states where they stand on what could be a controversial choice for Attorney General.”

Top Republican lawmakers, including Grassley, had already called on Obama to wait for the new Congress to select his nominee. 

Republican congressional aides have also questioned the feasibility of a lame-duck confirmation. The Senate does not reconvene until Nov. 12, and if lawmakers took the same seven work weeks they did for Mukasey, the soonest they could vote would be New Year's Eve — assuming a highly unlikely schedule with no breaks for Thanksgiving or Christmas.

The White House has not hinted who is on its shortlist to fill the job, although Labor Secretary Thomas PerezThomas Edward PerezClinton’s top five vice presidential picks Government social programs: Triumph of hope over evidence Labor’s 'wasteful spending and mismanagement” at Workers’ Comp MORE and Solicitor General Donald Verrilli are widely considered to be on the shortlist.

Former White House Counsel Kathy Ruemmler was also thought to be among the leading candidates, but new questions over her role in an internal White House investigation into whether a volunteer traveling ahead of the president to Colombia had hired a prostitute have clouded her candidacy.

Last week, White House spokesman Eric Schultz sidestepped questions about whether the allegations Ruemmler had not completed a full investigation would hurt her chances.

"Im not going to address whether any particular individuals are in contention for any particular slots, but I would say that, again, the review was conducted in an aggressive, thoughtful and thorough way," Schultz said.

The White House spokesman said, however, that naming a nominee was "a priority" for the administration.

"Attorney General Holder, over the past six years, has accomplished a lot. It will be tough shoes to fill, but there’s still a lot of work to be done. And so that’s something we’re looking to fill as soon as we can," Schultz said.

— Benjamin Goad contributed to this report, which was updated at 1:23 p.m.