Republicans are near-unanimous in demanding that President Barack Obama leave it to his successor to nominate a candidate to fill the Supreme Court seat of the late Justice Antonin Scalia. But the president insists he plans to come forward with a nominee — and that there’s plenty of time for the Senate to weigh in.

That sets up what could be an epic election-year clash between Obama and Republicans who say they’ll refuse to vote for his nominee, who could reshape the court for decades to come.

So who will Obama pick?

The White House had prepared for the possibility of liberal Justices Ruth Bader Ginsburg or Stephen Breyer retiring — but less so for a sudden vacancy of one of the court’s staunch conservatives like Scalia, said a former administration lawyer with knowledge of current White House planning. Now the White House is scrambling to put together a “short list” of candidates to be fully vetted, said the former official, who requested anonymity to discuss private conversations.

The biggest question facing Obama: whether he and his team feel there’s any realistic chance they can persuade Republicans to allow a vote.

If the answer is yes, Obama would have to try to find a perfect candidate with enough appeal to Republicans to change their minds. A sitting senator or someone recently confirmed might do the trick.

If the answer is no, Obama could try to use his selection to political advantage in this year’s elections by nominating someone who would spark backlash if Republicans oppose him or her. Picking a minority or someone from a battleground state in the election could rile up the Democratic base.

The White House said Sunday that Obama will nominate someone “in due time” once the Senate returns next week from recess. Obama took roughly a month to nominate Justices Elena Kagan and Sonia Sotomayor, but this time the clock is ticking like never before.

Obama hasn’t said who he’s considering, but some Cabinet members, politicians and current judges are being prominently floated as possible picks:

THE CABINET MEMBERS

—Attorney General Loretta Lynch

Though Lynch’s nomination was fraught with politics, she’s been recently confirmed and has been received relatively well by both parties since taking over the Justice Department less than a year ago. Before Obama promoted her, Lynch was a U.S. attorney for a key district based in Brooklyn. An African-American woman has never served on the Supreme Court. But her role in the Obama administration could prove divisive.

—Homeland Security Secretary Jeh Johnson

Johnson has serious credentials in many critical areas of the law, having served as the Pentagon’s general counsel and as a federal prosecutor. He has the benefit of having been Senate-confirmed multiple times — most recently in 2013 by an overwhelming majority. But Republicans loathe Obama’s executive actions on immigration that Johnson’s department put forward and are currently before the Supreme Court.

THE POLITICIANS

—California Attorney General Kamala Harris

Elected statewide in California in 2010, Harris is a longtime prosecutor and rising Democratic star who has drawn occasional comparisons with Obama. She’s currently running to replace California Sen. Barbara Boxer. Obama has made no secret of his affection for Harris; He once had to apologize after making an offhand joke that Harris was the country’s best-looking attorney general.

—Minnesota Sen. Amy Klobuchar

Picking a current colleague of the senators who will be voting on Obama’s nominee could be one strategy to increase prospects for a vote. Klobuchar, in her second Senate term, is a former prosecutor and member of the Senate Judiciary Committee.

—Utah Sen. Orrin Hatch

The Republican senator would be nominated only if Obama decided it would be better to pick a candidate Democrats didn’t love than risk a Republican successor making the choice for him. Sen. Lindsey Graham, R-S.C., has suggested Obama go with a “consensus pick” like Hatch. He’s also a key holdout in getting Senate approval for Obama’s Trans-Pacific Partnership trade deal.

THE JUDGES

—Sri Srinivasan, U.S. Court of Appeals for the District of Columbia Circuit

With a compelling personal story, Srinivasan has long been eyed for the high court. Born in India, Srinivasan clerked for former Justice Sandra Day O’Connor — a Republican. He has the added appeal of having been confirmed unanimously less than three years ago.

—Merrick Garland, chief judge, U.S. Court for Appeals of the District of Columbia Circuit

Garland is a Harvard Law School graduate whose name has long been in the mix. He’s considered a moderate judge and has experience on the D.C. circuit, which handles many cases involving administration actions.

—Paul Watford, U.S. Court of Appeals for the Ninth Circuit

Watford once served as a law clerk to Ginsburg, and worked as a federal prosecutor before Obama appointed him to the San Francisco-based court. An African-American, Watford was confirmed 61-34 in 2012.

—Jacqueline Nguyen, U.S. Court of Appeals for the Ninth Circuit

Nguyen would be the first Asian-American on the Supreme Court. She emigrated as a child from Vietnam and worked as an assistant U.S. attorney and a judge in California before Obama nominated her to federal courts.

—Patricia Millett, U.S. Court of Appeals for the District of Columbia Circuit

Obama nominated Millett in 2013 after John Roberts joined the Supreme Court as chief justice. Her nomination lingered for months amid a fight about the filibuster. Millett had experience in the U.S. Solicitor General’s office, arguing dozens of cases before the Supreme Court.

—Robert Wilkins, U.S. Court of Appeals for the District of Columbia Circuit

A chemical engineer by training, Wilkins was a public defender before being appointed by Obama to federal positions. Wilkins, an African-American, was raised by a single mother and is known for his involvement in civil rights issues.

—Jane Kelly, U.S. Court of Appeals for the Eighth Circuit

Kelly, a former public defender, was unanimously confirmed to the St. Louis-based court. She’s earned praise from Sen. Chuck Grassley, R-Iowa, who chairs the Senate Judiciary Committee. But Grassley has joined Republicans in urging delay until after the election.

(AP)