WASHINGTON (AP) — President Barack Obama does not plan to announce his choice for attorney general before the November elections, shielding the nomination from the rough-and-tumble of midterm election politics.

Delaying an announcement of a replacement for outgoing Attorney General Eric Holder, however, will set up a likely showdown with a lame duck Senate late this year on a compressed timetable.

Senate Democrats have asked Obama to wait so controversy doesn’t arise over whether they will support a specific nominee and the delay gives Obama more time to consider his options.

A White House official told The Associated Press Tuesday that the president has not yet decided who he wants to replace Holder, a longtime friend who has led the Justice Department the entire six years Obama has been in office. Obama aides did not begin seriously considering candidates until Holder announced on Sept. 25 that he will resign when his replacement is confirmed, although his departure had been expected this year.

The White House is preparing for the prospect of trying to push through a nominee in the year-end congressional session while Democrats still have a 10-seat majority in the Senate. Obama faces the likelihood of an even tougher challenge to win confirmation if he waits until the new Senate is seated early next year, since Republicans are expected to pick up seats in the midterm, if not win outright control.

Some Senate Republicans have called on Obama to wait until the new Senate is seated in January to make the nomination. Republicans are promising close scrutiny of Obama’s nominee after waging a series of battles with Holder.

Iowa Sen. Chuck Grassley, the leading Republican on the Judiciary Committee that will hold hearings on the nominee, said Democrats are trying to “avoid making clear to the voters of their states where they stand on what could be a controversial choice for attorney general.”

“This timing shows, once again, that the president and Democrat Senate leaders are willing to play politics with important policy decisions,” Grassley said.

The lame duck timetable covers just seven legislative calendar weeks, not accounting time off for holiday recesses. But the White House has pointed out there is precedent for such a move. The day after the 2006 midterm, President George W. Bush nominated Robert Gates as secretary of defense and he was confirmed in less than a month with bipartisan support.

Obama seems to be looking most closely at those who already have served in his administration. Top contenders include Solicitor General Don Verrilli, former White House counsel Kathy Ruemmler and Labor Secretary Tom Perez, although those involved with the process say other candidates haven’t been ruled out.

Verrilli is Obama’s Supreme Court lawyer who successfully defended his health care law from a constitutional challenge two years ago. Verrilli has extensive trial experience, including landmark battles over telecommunications competition and online piracy plus pro bono work against death penalty cases. Republicans already are signaling that Verrilli’s light experience on national security would be an issue they will raise at a time when the United States is battling a violent terrorist threat overseas.

Perez has a personal story that’s the tale of the American Dream, rising to the Cabinet from humble beginnings as a child of Dominican immigrants and one-time trash collector. In Obama’s first term, he led the Justice Department’s civil rights division and won praise from Democrats for aggressive enforcement of voting rights and other laws. Holder was focused on civil rights enforcement, and a selection of Perez would signal that Obama wants that work to continue to be a priority.

But Perez also lacks foreign policy credentials and his nomination to Labor was divisive, with approval on a 54-46 party-line vote. Republicans accused Perez of selectively enforcing laws according to his political views and accused him of supporting efforts to sidestep federal immigration laws when he was a local government official in Maryland.

Ruemmler would bring broad experience and a close relationship with Obama after serving three years as his lead counsel and a member of his national security team. She also has the law enforcement chops of a former federal prosecutor best known for winning criminal convictions against Enron executives Ken Lay and Jeffrey Skilling.

But she also would certainly face tough GOP inspection for her handling of White House controversies involving the IRS, Benghazi and the investigation of a White House volunteer in a prostitution scandal. And since she’s never been through Senate confirmation before, congressional aides say she’d present a bigger challenge to process on a compressed schedule.

Other candidates whom administration officials have mentioned for consideration include Preet Bharara, the U.S. attorney for the Southern District of New York; Jenny Durkan, who recently announced she’s stepping down as U.S. attorney in Washington state; former Homeland Security Secretary Janet Napolitano; Tony West, who recently resigned as the No. 3 at the Justice Department and has accepted a job at Pepsico; and Deputy Homeland Security Secretary Alejandro Mayorkas.