The White House is preparing to defy Republicans and possibly push through the confirmation of a new attorney general in the lame duck session of Congress if Democrats lose control of the Senate in November’s midterm elections.



Though refusing to speculate on the exact timing of a replacement for Eric Holder, who announced his resignation on Thursday, Obama administration officials began laying the ground for such a strategy by listing precedents under previous presidents. The stakes have been heightened after a recent rule change under Senate majority leader Harry Reid which means that only 51 votes are required to confirm White House nominations rather than the 60 previously needed to avoid a filibuster.



The examples being cited by the White House include Robert Gates, defence secretary under George W Bush, who was confirmed in December 2006 despite the Republicans losing control of the Senate in the previous month’s elections.



“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,” Obama spokesman Josh Earnest told reporters on Friday.



The Gates example may carry little weight with Republicans who would point out that he was a bipartisan figure confirmed with near-unanimous support and who was also later appointed by Obama, whereas they fear a more divisive candidate in the mold of Holder. On the other hand, Democrats argue Republicans have become much more obstructive than ever before, which was one reason they felt it necessary to change the filibuster rules.



The prospect of a lame duck confirmation vote has angered Republicans, not least because such a vote could potentially rely on Democratic senators who had lost their elections but who would still be in office until the new Congress is sworn in next year.



Earnest also pointed to the appointment of Holder’s predecessor Michael Mukasey, who was also nominated by Bush but confirmed by a Democratic-controlled Senate.



“Without announcing any sort of decisions that have been made internally about timelines,” he added, “I guess the point I’m trying to make is that either way, whether or not a nominee would need to be confirmed in a lame duck session or would need to be confirmed by a new Senate, that in either case we would anticipate that the Senate would act promptly in a bipartisan fashion.”



Holder is reported to have made his decision to retire now, after six years in office, partly because it represented the last practical window for him to go without leaving president Barack Obama with difficulty pushing his chosen successor through the Senate confirmation process.



Current polling suggests Republicans stand a reasonable chance of gaining control of the Senate in November, particularly because many of the seats defended by Democrats are in states that voted against Obama in the last general election.



Holder has been accused of being a divisive attorney general by many Republicans and any attempt by the White House to appoint a relatively liberal candidate in his place could serve as a rallying point for the party.