Which of President Obama’s closest advisers is the rightful heir to his legacy, his vice president Joe Biden or his former secretary of State Hillary Clinton?
That’s a delicate question that Mr. Obama may have to face as speculation grows that Mr. Biden might step up to challenge Mrs. Clinton.
The White House on Monday raised the prospect that Obama could endorse a candidate in the Democratic primary, though there’s an assumption among others close to the president that he will stay neutral.
"Certainly he's got something at stake here," White House spokesman Josh Earnest said of Obama's interest in the 2016 election.
Responding to questions from reporters, Mr. Earnest said Obama viewed his selection of Biden as a running mate as the smartest decision of his political career.
"I think that should give you some sense of the president's view of Vice President Biden's aptitude for the top job," Earnest said.
Obama is close to both leaders and so far has been reluctant to weigh in on the Democratic presidential primary.
After the 2008 primary race between Obama and Clinton, the two turned their political rivalry into an alliance. Clinton left the administration in early 2013 after four years as Obama's secretary of State, but she and the president still get together for occasional meetings.
Meanwhile, Obama and Biden appear to have developed a genuine friendship during their six-and-a-half years in the White House. According to reports, Biden and Obama had lunch at the White House on Monday after the president returned from a two-week vacation on the Massachusetts island of Martha's Vineyard.
But how exactly the president would handle a hypothetical Clinton-Biden contest remains an open question.
"Biden, as the president's partner, would be closely identified with the Obama legacy," said David Axelrod, a longtime Obama political adviser. However, he added, "any Democrat will carry the benefits and burdens of Obama into this election."
The Clinton campaign is wrestling to overcome the controversy over her use of a private email server during her time as secretary – and her choice to delete e-mails she deemed "personal."
This report contains material from the Associated Press.