Joe Biden's wife may share his misgivings about another bid for the presidency

Vice-President Joe Biden's reluctance to enter the presidential race centres on his family. His wife, Jill, has never relished political life and is said to share his misgivings about whether the Bidens are emotionally equipped for another campaign.

Those close to the second lady say she won't stand in the way of her husband's political ambitions, but her feelings about a White House bid are a major factor in Biden's decision. Only three months after losing their 46-year-old son, Beau, to brain cancer, the 72-year-old Biden appeared sombre and weary at an Atlanta synagogue Thursday night as he pondered his family's readiness.

"The honest-to-God answer is I just don't know," he said.

Biden is deliberating about entering a Democratic primary race that includes front runner Hillary Clinton and long-shot candidates including Senator Bernie Sanders. Biden's entry would shake up the campaign at a time when some Democrats would like to see more options.

Clinton has locked up much of the Democratic establishment and few expected Biden to enter the race. But the former secretary of state's recent slide in Democratic primary polls and questions surrounding her use of a private email account and server while at the State Department have prompted the vice president to explore a campaign to succeed Barack Obama.

While the vice president's deliberations have played out in semi-public fashion, Jill Biden's have taken place away from the spotlight. She has yet to discuss in detail with her staff her views on a possible presidential run. But she has been looking out for her husband and echoing his concerns about whether he can completely devote himself to a hard-fought campaign, according to several people who have spoken to her.